Merge branch 'v2-prototype' into fix/five_decimal_scenario

* v2-prototype: (75 commits)
  Update relayer grid tiles to use Text
  Fix build
  Update file structure
  Update 2.0.0 artifacts
  Move ledgerhq module declarations to typescript-typings
  Export LedgerEthereumClient type in subproviders
  Update artifacts
  Add logging and updated artifacts
  Fix migrations
  Run prettier
  Add Kovan artifacts
  Use ledger subprovider
  Add Kovan migrations
  Remove state variable from Link component in Portal
  Make registerAssetProxy append only
  Update staging api link
  Change getTransactionReceipt to awaitTransactionMined
  Move /docs route to the end
  Remove extra call to scrollIntoView for wallet in onboarding
  Update expectRevertReasonOrAlwaysFailingTransactionAsync to check status codes
  ...

63 files changed, 7750 insertions, 0 deletions

diff --git a/packages/contracts/src/2.0.0/multisig/MultiSigWallet.sol b/packages/contracts/src/2.0.0/multisig/MultiSigWallet.sol
new file mode 100644
index 000000000..79fd92029
--- /dev/null
+++ b/packages/contracts/src/2.0.0/multisig/MultiSigWallet.sol
@@ -0,0 +1,365 @@
+pragma solidity ^0.4.10;
+
+/// @title Multisignature wallet - Allows multiple parties to agree on transactions before execution.
+/// @author Stefan George - <stefan.george@consensys.net>
+contract MultiSigWallet {
+
+    uint constant public MAX_OWNER_COUNT = 50;
+
+    event Confirmation(address indexed sender, uint indexed transactionId);
+    event Revocation(address indexed sender, uint indexed transactionId);
+    event Submission(uint indexed transactionId);
+    event Execution(uint indexed transactionId);
+    event ExecutionFailure(uint indexed transactionId);
+    event Deposit(address indexed sender, uint value);
+    event OwnerAddition(address indexed owner);
+    event OwnerRemoval(address indexed owner);
+    event RequirementChange(uint required);
+
+    mapping (uint => Transaction) public transactions;
+    mapping (uint => mapping (address => bool)) public confirmations;
+    mapping (address => bool) public isOwner;
+    address[] public owners;
+    uint public required;
+    uint public transactionCount;
+
+    struct Transaction {
+        address destination;
+        uint value;
+        bytes data;
+        bool executed;
+    }
+
+    modifier onlyWallet() {
+        if (msg.sender != address(this))
+            throw;
+        _;
+    }
+
+    modifier ownerDoesNotExist(address owner) {
+        if (isOwner[owner])
+            throw;
+        _;
+    }
+
+    modifier ownerExists(address owner) {
+        if (!isOwner[owner])
+            throw;
+        _;
+    }
+
+    modifier transactionExists(uint transactionId) {
+        if (transactions[transactionId].destination == 0)
+            throw;
+        _;
+    }
+
+    modifier confirmed(uint transactionId, address owner) {
+        if (!confirmations[transactionId][owner])
+            throw;
+        _;
+    }
+
+    modifier notConfirmed(uint transactionId, address owner) {
+        if (confirmations[transactionId][owner])
+            throw;
+        _;
+    }
+
+    modifier notExecuted(uint transactionId) {
+        if (transactions[transactionId].executed)
+            throw;
+        _;
+    }
+
+    modifier notNull(address _address) {
+        if (_address == 0)
+            throw;
+        _;
+    }
+
+    modifier validRequirement(uint ownerCount, uint _required) {
+        if (   ownerCount > MAX_OWNER_COUNT
+            || _required > ownerCount
+            || _required == 0
+            || ownerCount == 0)
+            throw;
+        _;
+    }
+
+    /// @dev Fallback function allows to deposit ether.
+    function()
+        payable
+    {
+        if (msg.value > 0)
+            Deposit(msg.sender, msg.value);
+    }
+
+    /*
+     * Public functions
+     */
+    /// @dev Contract constructor sets initial owners and required number of confirmations.
+    /// @param _owners List of initial owners.
+    /// @param _required Number of required confirmations.
+    function MultiSigWallet(address[] _owners, uint _required)
+        public
+        validRequirement(_owners.length, _required)
+    {
+        for (uint i=0; i<_owners.length; i++) {
+            if (isOwner[_owners[i]] || _owners[i] == 0)
+                throw;
+            isOwner[_owners[i]] = true;
+        }
+        owners = _owners;
+        required = _required;
+    }
+
+    /// @dev Allows to add a new owner. Transaction has to be sent by wallet.
+    /// @param owner Address of new owner.
+    function addOwner(address owner)
+        public
+        onlyWallet
+        ownerDoesNotExist(owner)
+        notNull(owner)
+        validRequirement(owners.length + 1, required)
+    {
+        isOwner[owner] = true;
+        owners.push(owner);
+        OwnerAddition(owner);
+    }
+
+    /// @dev Allows to remove an owner. Transaction has to be sent by wallet.
+    /// @param owner Address of owner.
+    function removeOwner(address owner)
+        public
+        onlyWallet
+        ownerExists(owner)
+    {
+        isOwner[owner] = false;
+        for (uint i=0; i<owners.length - 1; i++)
+            if (owners[i] == owner) {
+                owners[i] = owners[owners.length - 1];
+                break;
+            }
+        owners.length -= 1;
+        if (required > owners.length)
+            changeRequirement(owners.length);
+        OwnerRemoval(owner);
+    }
+
+    /// @dev Allows to replace an owner with a new owner. Transaction has to be sent by wallet.
+    /// @param owner Address of owner to be replaced.
+    /// @param owner Address of new owner.
+    function replaceOwner(address owner, address newOwner)
+        public
+        onlyWallet
+        ownerExists(owner)
+        ownerDoesNotExist(newOwner)
+    {
+        for (uint i=0; i<owners.length; i++)
+            if (owners[i] == owner) {
+                owners[i] = newOwner;
+                break;
+            }
+        isOwner[owner] = false;
+        isOwner[newOwner] = true;
+        OwnerRemoval(owner);
+        OwnerAddition(newOwner);
+    }
+
+    /// @dev Allows to change the number of required confirmations. Transaction has to be sent by wallet.
+    /// @param _required Number of required confirmations.
+    function changeRequirement(uint _required)
+        public
+        onlyWallet
+        validRequirement(owners.length, _required)
+    {
+        required = _required;
+        RequirementChange(_required);
+    }
+
+    /// @dev Allows an owner to submit and confirm a transaction.
+    /// @param destination Transaction target address.
+    /// @param value Transaction ether value.
+    /// @param data Transaction data payload.
+    /// @return Returns transaction ID.
+    function submitTransaction(address destination, uint value, bytes data)
+        public
+        returns (uint transactionId)
+    {
+        transactionId = addTransaction(destination, value, data);
+        confirmTransaction(transactionId);
+    }
+
+    /// @dev Allows an owner to confirm a transaction.
+    /// @param transactionId Transaction ID.
+    function confirmTransaction(uint transactionId)
+        public
+        ownerExists(msg.sender)
+        transactionExists(transactionId)
+        notConfirmed(transactionId, msg.sender)
+    {
+        confirmations[transactionId][msg.sender] = true;
+        Confirmation(msg.sender, transactionId);
+        executeTransaction(transactionId);
+    }
+
+    /// @dev Allows an owner to revoke a confirmation for a transaction.
+    /// @param transactionId Transaction ID.
+    function revokeConfirmation(uint transactionId)
+        public
+        ownerExists(msg.sender)
+        confirmed(transactionId, msg.sender)
+        notExecuted(transactionId)
+    {
+        confirmations[transactionId][msg.sender] = false;
+        Revocation(msg.sender, transactionId);
+    }
+
+    /// @dev Allows anyone to execute a confirmed transaction.
+    /// @param transactionId Transaction ID.
+    function executeTransaction(uint transactionId)
+        public
+        notExecuted(transactionId)
+    {
+        if (isConfirmed(transactionId)) {
+            Transaction tx = transactions[transactionId];
+            tx.executed = true;
+            if (tx.destination.call.value(tx.value)(tx.data))
+                Execution(transactionId);
+            else {
+                ExecutionFailure(transactionId);
+                tx.executed = false;
+            }
+        }
+    }
+
+    /// @dev Returns the confirmation status of a transaction.
+    /// @param transactionId Transaction ID.
+    /// @return Confirmation status.
+    function isConfirmed(uint transactionId)
+        public
+        constant
+        returns (bool)
+    {
+        uint count = 0;
+        for (uint i=0; i<owners.length; i++) {
+            if (confirmations[transactionId][owners[i]])
+                count += 1;
+            if (count == required)
+                return true;
+        }
+    }
+
+    /*
+     * Internal functions
+     */
+    /// @dev Adds a new transaction to the transaction mapping, if transaction does not exist yet.
+    /// @param destination Transaction target address.
+    /// @param value Transaction ether value.
+    /// @param data Transaction data payload.
+    /// @return Returns transaction ID.
+    function addTransaction(address destination, uint value, bytes data)
+        internal
+        notNull(destination)
+        returns (uint transactionId)
+    {
+        transactionId = transactionCount;
+        transactions[transactionId] = Transaction({
+            destination: destination,
+            value: value,
+            data: data,
+            executed: false
+        });
+        transactionCount += 1;
+        Submission(transactionId);
+    }
+
+    /*
+     * Web3 call functions
+     */
+    /// @dev Returns number of confirmations of a transaction.
+    /// @param transactionId Transaction ID.
+    /// @return Number of confirmations.
+    function getConfirmationCount(uint transactionId)
+        public
+        constant
+        returns (uint count)
+    {
+        for (uint i=0; i<owners.length; i++)
+            if (confirmations[transactionId][owners[i]])
+                count += 1;
+    }
+
+    /// @dev Returns total number of transactions after filers are applied.
+    /// @param pending Include pending transactions.
+    /// @param executed Include executed transactions.
+    /// @return Total number of transactions after filters are applied.
+    function getTransactionCount(bool pending, bool executed)
+        public
+        constant
+        returns (uint count)
+    {
+        for (uint i=0; i<transactionCount; i++)
+            if (   pending && !transactions[i].executed
+                || executed && transactions[i].executed)
+                count += 1;
+    }
+
+    /// @dev Returns list of owners.
+    /// @return List of owner addresses.
+    function getOwners()
+        public
+        constant
+        returns (address[])
+    {
+        return owners;
+    }
+
+    /// @dev Returns array with owner addresses, which confirmed transaction.
+    /// @param transactionId Transaction ID.
+    /// @return Returns array of owner addresses.
+    function getConfirmations(uint transactionId)
+        public
+        constant
+        returns (address[] _confirmations)
+    {
+        address[] memory confirmationsTemp = new address[](owners.length);
+        uint count = 0;
+        uint i;
+        for (i=0; i<owners.length; i++)
+            if (confirmations[transactionId][owners[i]]) {
+                confirmationsTemp[count] = owners[i];
+                count += 1;
+            }
+        _confirmations = new address[](count);
+        for (i=0; i<count; i++)
+            _confirmations[i] = confirmationsTemp[i];
+    }
+
+    /// @dev Returns list of transaction IDs in defined range.
+    /// @param from Index start position of transaction array.
+    /// @param to Index end position of transaction array.
+    /// @param pending Include pending transactions.
+    /// @param executed Include executed transactions.
+    /// @return Returns array of transaction IDs.
+    function getTransactionIds(uint from, uint to, bool pending, bool executed)
+        public
+        constant
+        returns (uint[] _transactionIds)
+    {
+        uint[] memory transactionIdsTemp = new uint[](transactionCount);
+        uint count = 0;
+        uint i;
+        for (i=0; i<transactionCount; i++)
+            if (   pending && !transactions[i].executed
+                || executed && transactions[i].executed)
+            {
+                transactionIdsTemp[count] = i;
+                count += 1;
+            }
+        _transactionIds = new uint[](to - from);
+        for (i=from; i<to; i++)
+            _transactionIds[i - from] = transactionIdsTemp[i];
+    }
+}
diff --git a/packages/contracts/src/2.0.0/multisig/MultiSigWalletWithTimeLock.sol b/packages/contracts/src/2.0.0/multisig/MultiSigWalletWithTimeLock.sol
new file mode 100644
index 000000000..9766c2158
--- /dev/null
+++ b/packages/contracts/src/2.0.0/multisig/MultiSigWalletWithTimeLock.sol
@@ -0,0 +1,132 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.10;
+
+import "./MultiSigWallet.sol";
+
+/// @title Multisignature wallet with time lock- Allows multiple parties to execute a transaction after a time lock has passed.
+/// @author Amir Bandeali - <amir@0xProject.com>
+contract MultiSigWalletWithTimeLock is MultiSigWallet {
+
+    event ConfirmationTimeSet(uint indexed transactionId, uint confirmationTime);
+    event TimeLockChange(uint secondsTimeLocked);
+
+    uint public secondsTimeLocked;
+
+    mapping (uint => uint) public confirmationTimes;
+
+    modifier notFullyConfirmed(uint transactionId) {
+        require(!isConfirmed(transactionId));
+        _;
+    }
+
+    modifier fullyConfirmed(uint transactionId) {
+        require(isConfirmed(transactionId));
+        _;
+    }
+
+    modifier pastTimeLock(uint transactionId) {
+        require(block.timestamp >= confirmationTimes[transactionId] + secondsTimeLocked);
+        _;
+    }
+
+    /*
+     * Public functions
+     */
+
+    /// @dev Contract constructor sets initial owners, required number of confirmations, and time lock.
+    /// @param _owners List of initial owners.
+    /// @param _required Number of required confirmations.
+    /// @param _secondsTimeLocked Duration needed after a transaction is confirmed and before it becomes executable, in seconds.
+    function MultiSigWalletWithTimeLock(address[] _owners, uint _required, uint _secondsTimeLocked)
+        public
+        MultiSigWallet(_owners, _required)
+    {
+        secondsTimeLocked = _secondsTimeLocked;
+    }
+
+    /// @dev Changes the duration of the time lock for transactions.
+    /// @param _secondsTimeLocked Duration needed after a transaction is confirmed and before it becomes executable, in seconds.
+    function changeTimeLock(uint _secondsTimeLocked)
+        public
+        onlyWallet
+    {
+        secondsTimeLocked = _secondsTimeLocked;
+        TimeLockChange(_secondsTimeLocked);
+    }
+
+    /// @dev Allows an owner to confirm a transaction.
+    /// @param transactionId Transaction ID.
+    function confirmTransaction(uint transactionId)
+        public
+        ownerExists(msg.sender)
+        transactionExists(transactionId)
+        notConfirmed(transactionId, msg.sender)
+        notFullyConfirmed(transactionId)
+    {
+        confirmations[transactionId][msg.sender] = true;
+        Confirmation(msg.sender, transactionId);
+        if (isConfirmed(transactionId)) {
+            setConfirmationTime(transactionId, block.timestamp);
+        }
+    }
+
+    /// @dev Allows an owner to revoke a confirmation for a transaction.
+    /// @param transactionId Transaction ID.
+    function revokeConfirmation(uint transactionId)
+        public
+        ownerExists(msg.sender)
+        confirmed(transactionId, msg.sender)
+        notExecuted(transactionId)
+        notFullyConfirmed(transactionId)
+    {
+        confirmations[transactionId][msg.sender] = false;
+        Revocation(msg.sender, transactionId);
+    }
+
+    /// @dev Allows anyone to execute a confirmed transaction.
+    /// @param transactionId Transaction ID.
+    function executeTransaction(uint transactionId)
+        public
+        notExecuted(transactionId)
+        fullyConfirmed(transactionId)
+        pastTimeLock(transactionId)
+    {
+        Transaction storage tx = transactions[transactionId];
+        tx.executed = true;
+        if (tx.destination.call.value(tx.value)(tx.data))
+            Execution(transactionId);
+        else {
+            ExecutionFailure(transactionId);
+            tx.executed = false;
+        }
+    }
+
+    /*
+     * Internal functions
+     */
+
+    /// @dev Sets the time of when a submission first passed.
+    function setConfirmationTime(uint transactionId, uint confirmationTime)
+        internal
+    {
+        confirmationTimes[transactionId] = confirmationTime;
+        ConfirmationTimeSet(transactionId, confirmationTime);
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
new file mode 100644
index 000000000..aed62f54f
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
@@ -0,0 +1,132 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../utils/LibBytes/LibBytes.sol";
+import "./MixinAuthorizable.sol";
+
+contract ERC20Proxy is
+    MixinAuthorizable
+{
+    // Id of this proxy.
+    bytes4 constant PROXY_ID = bytes4(keccak256("ERC20Token(address)"));
+    
+    function () 
+        external
+    {
+        assembly {
+            // The first 4 bytes of calldata holds the function selector
+            let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)
+
+            // `transferFrom` will be called with the following parameters:
+            // assetData Encoded byte array.
+            // from Address to transfer asset from.
+            // to Address to transfer asset to.
+            // amount Amount of asset to transfer.
+            // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+            if eq(selector, 0xa85e59e400000000000000000000000000000000000000000000000000000000) {
+
+                // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
+                // where k is the key left padded to 32 bytes and p is the storage slot
+                let start := mload(64)
+                mstore(start, and(caller, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(start, 32), authorized_slot)
+
+                // Revert if authorized[msg.sender] == false
+                if iszero(sload(keccak256(start, 64))) {
+                    // Revert with `Error("SENDER_NOT_AUTHORIZED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+                
+                /////// Token contract address ///////
+                // The token address is found as follows:
+                // * It is stored at offset 4 in `assetData` contents.
+                // * This is stored at offset 32 from `assetData`.
+                // * The offset to `assetData` from Params is stored at offset
+                //   4 in calldata.
+                // * The offset of Params in calldata is 4.
+                // So we read location 4 and add 32 + 4 + 4 to it.
+                let token := calldataload(add(calldataload(4), 40))
+                
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFrom` selector.
+                // Any trailing data in transferFromSelector will be
+                // overwritten in the next `mstore` call.
+                mstore(0, 0x23b872dd00000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // We copy the fields `from`, `to` and `amount` in bulk
+                // from our own calldata to the new calldata.
+                calldatacopy(4, 36, 96)
+
+                /////// Call `token.transferFrom` using the calldata ///////
+                let success := call(
+                    gas,            // forward all gas
+                    token,          // call address of token contract
+                    0,              // don't send any ETH
+                    0,              // pointer to start of input
+                    100,            // length of input
+                    0,              // write output over input
+                    32              // output size should be 32 bytes
+                )
+
+                /////// Check return data. ///////
+                // If there is no return data, we assume the token incorrectly
+                // does not return a bool. In this case we expect it to revert
+                // on failure, which was handled above.
+                // If the token does return data, we require that it is a single
+                // nonzero 32 bytes value.
+                // So the transfer succeeded if the call succeeded and either
+                // returned nothing, or returned a non-zero 32 byte value. 
+                success := and(success, or(
+                    iszero(returndatasize),
+                    and(
+                        eq(returndatasize, 32),
+                        gt(mload(0), 0)
+                    )
+                ))
+                if success {
+                    return(0, 0)
+                }
+                
+                // Revert with `Error("TRANSFER_FAILED")`
+                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                mstore(64, 0x0000000f5452414e534645525f4641494c454400000000000000000000000000)
+                mstore(96, 0)
+                revert(0, 100)
+            }
+        }
+    }
+
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4)
+    {
+        return PROXY_ID;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
new file mode 100644
index 000000000..b73dc36cc
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
@@ -0,0 +1,218 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../utils/LibBytes/LibBytes.sol";
+import "./MixinAuthorizable.sol";
+
+contract ERC721Proxy is
+    MixinAuthorizable
+{
+    // Id of this proxy.
+    bytes4 constant PROXY_ID = bytes4(keccak256("ERC721Token(address,uint256,bytes)"));
+
+    function () 
+        external
+    {
+        assembly {
+            // The first 4 bytes of calldata holds the function selector
+            let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)
+
+            // `transferFrom` will be called with the following parameters:
+            // assetData Encoded byte array.
+            // from Address to transfer asset from.
+            // to Address to transfer asset to.
+            // amount Amount of asset to transfer.
+            // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+            if eq(selector, 0xa85e59e400000000000000000000000000000000000000000000000000000000) {
+
+                // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
+                // where k is the key left padded to 32 bytes and p is the storage slot
+                let start := mload(64)
+                mstore(start, and(caller, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(start, 32), authorized_slot)
+
+                // Revert if authorized[msg.sender] == false
+                if iszero(sload(keccak256(start, 64))) {
+                    // Revert with `Error("SENDER_NOT_AUTHORIZED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+
+                // `transferFrom`.
+                // The function is marked `external`, so no abi decodeding is done for
+                // us. Instead, we expect the `calldata` memory to contain the
+                // following:
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 4 * 32  | function parameters:                |
+                // |          | 4      |         |   1. offset to assetData (*)        |
+                // |          | 36     |         |   2. from                           |
+                // |          | 68     |         |   3. to                             |
+                // |          | 100    |         |   4. amount                         |
+                // | Data     |        |         | assetData:                          |
+                // |          | 132    | 32      | assetData Length                    |
+                // |          | 164    | **      | assetData Contents                  |
+                //
+                // (*): offset is computed from start of function parameters, so offset
+                //      by an additional 4 bytes in the calldata.
+                //
+                // WARNING: The ABIv2 specification allows additional padding between
+                //          the Params and Data section. This will result in a larger
+                //          offset to assetData.
+                
+                // Asset data itself is encoded as follows:
+                //
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 3 * 32  | function parameters:                |
+                // |          | 4      | 12 + 20 |   1. token address                  |
+                // |          | 36     |         |   2. tokenId                        |
+                // |          | 68     |         |   3. offset to receiverData (*)     |
+                // | Data     |        |         | receiverData:                       |
+                // |          | 100    | 32      | receiverData Length                 |
+                // |          | 132    | **      | receiverData Contents               |
+                
+                // We construct calldata for the `token.safeTransferFrom` ABI.
+                // The layout of this calldata is in the table below.
+                // 
+                // | Area     | Offset | Length  | Contents                            |
+                // |----------|--------|---------|-------------------------------------|
+                // | Header   | 0      | 4       | function selector                   |
+                // | Params   |        | 4 * 32  | function parameters:                |
+                // |          | 4      |         |   1. from                           |
+                // |          | 36     |         |   2. to                             |
+                // |          | 68     |         |   3. tokenId                        |
+                // |          | 100    |         |   4. offset to receiverData (*)     |
+                // | Data     |        |         | receiverData:                       |
+                // |          | 132    | 32      | receiverData Length                 |
+                // |          | 164    | **      | receiverData Contents               |
+
+                // There exists only 1 of each token.
+                // require(amount == 1, "INVALID_AMOUNT")
+                if sub(calldataload(100), 1) {
+                    // Revert with `Error("INVALID_AMOUNT")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000000e494e56414c49445f414d4f554e540000000000000000000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+                
+                // Require assetData to be at least 132 bytes
+                let offset := calldataload(4)
+                if lt(calldataload(add(offset, 4)), 132) {
+                    // Revert with `Error("LENGTH_GREATER_THAN_131_REQUIRED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x000000204c454e4754485f475245415445525f5448414e5f3133315f52455155)
+                    mstore(96, 0x4952454400000000000000000000000000000000000000000000000000000000)
+                    revert(0, 100)
+                }
+                
+                /////// Setup State ///////
+                // `cdStart` is the start of the calldata for
+                // `token.safeTransferFrom` (equal to free memory ptr).
+                let cdStart := mload(64)
+                // `dataAreaLength` is the total number of words
+                // needed to store `receiverData`
+                // As-per the ABI spec, this value is padded up to
+                // the nearest multiple of 32,
+                // and includes 32-bytes for length.
+                // It's calculated as folows:
+                //      - Unpadded length in bytes = `mload(receiverData) + 32`
+                //      - Add 31 to convert rounding down to rounding up.
+                //        Combined with the previous and this is `63`.
+                //      - Round down to nearest multiple of 32 by clearing
+                //        bits 0x1F. This is done with `and` and a mask.
+
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFromSelector`.
+                // Any trailing data in transferFromSelector will be
+                // overwritten in the next `mstore` call.
+                mstore(cdStart, 0xb88d4fde00000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // Each parameter is padded to 32-bytes.
+                // The entire Params Area is 128 bytes.
+                // Notes:
+                //   1. A 20-byte mask is applied to addresses
+                //      to zero-out the unused bytes.
+                //   2. The offset to `receiverData` is the length
+                //      of the Params Area (128 bytes).
+                
+                let length := calldataload(add(offset, 136))
+                let token := calldataload(add(offset, 40))
+                
+                // Round length up to multiple of 32
+                length := and(add(length, 31), 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFE0)
+                
+                // Copy `from` and `to`
+                calldatacopy(add(cdStart, 4), 36, 64)
+                
+                // TokenId
+                mstore(add(cdStart, 68), calldataload(add(offset, 72)))
+                
+                // Offset to receiverData
+                mstore(add(cdStart, 100), 128)
+                
+                // receiverData (including length)
+                calldatacopy(add(cdStart, 132), add(offset, 136), add(length, 32))
+                
+                /////// Call `token.safeTransferFrom` using the calldata ///////
+                let success := call(
+                    gas,                    // forward all gas
+                    token,                  // call address of token contract
+                    0,                      // don't send any ETH
+                    cdStart,                // pointer to start of input
+                    add(length, 164),       // length of input
+                    0,                      // write output to null
+                    0                       // output size is 0 bytes
+                )
+                if success {
+                    return(0, 0)
+                }
+                
+                // Revert with `Error("TRANSFER_FAILED")`
+                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                mstore(64, 0x0000000f5452414e534645525f4641494c454400000000000000000000000000)
+                mstore(96, 0)
+                revert(0, 100)
+            }
+        }
+    }
+
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4)
+    {
+        return PROXY_ID;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol
new file mode 100644
index 000000000..3b9584a44
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol
@@ -0,0 +1,118 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../utils/Ownable/Ownable.sol";
+import "./mixins/MAuthorizable.sol";
+
+contract MixinAuthorizable is
+    Ownable,
+    MAuthorizable
+{
+
+    /// @dev Only authorized addresses can invoke functions with this modifier.
+    modifier onlyAuthorized {
+        require(
+            authorized[msg.sender],
+            "SENDER_NOT_AUTHORIZED"
+        );
+        _;
+    }
+
+    mapping (address => bool) public authorized;
+    address[] public authorities;
+
+    /// @dev Authorizes an address.
+    /// @param target Address to authorize.
+    function addAuthorizedAddress(address target)
+        external
+        onlyOwner
+    {
+        require(
+            !authorized[target],
+            "TARGET_ALREADY_AUTHORIZED"
+        );
+
+        authorized[target] = true;
+        authorities.push(target);
+        emit AuthorizedAddressAdded(target, msg.sender);
+    }
+
+    /// @dev Removes authorizion of an address.
+    /// @param target Address to remove authorization from.
+    function removeAuthorizedAddress(address target)
+        external
+        onlyOwner
+    {
+        require(
+            authorized[target],
+            "TARGET_NOT_AUTHORIZED"
+        );
+
+        delete authorized[target];
+        for (uint256 i = 0; i < authorities.length; i++) {
+            if (authorities[i] == target) {
+                authorities[i] = authorities[authorities.length - 1];
+                authorities.length -= 1;
+                break;
+            }
+        }
+        emit AuthorizedAddressRemoved(target, msg.sender);
+    }
+
+    /// @dev Removes authorizion of an address.
+    /// @param target Address to remove authorization from.
+    /// @param index Index of target in authorities array.
+    function removeAuthorizedAddressAtIndex(
+        address target,
+        uint256 index
+    )
+        external
+        onlyOwner
+    {
+        require(
+            authorized[target],
+            "TARGET_NOT_AUTHORIZED"
+        );
+        require(
+            index < authorities.length,
+            "INDEX_OUT_OF_BOUNDS"
+        );
+        require(
+            authorities[index] == target,
+            "AUTHORIZED_ADDRESS_MISMATCH"
+        );
+
+        delete authorized[target];
+        authorities[index] = authorities[authorities.length - 1];
+        authorities.length -= 1;
+        emit AuthorizedAddressRemoved(target, msg.sender);
+    }
+
+    /// @dev Gets all authorized addresses.
+    /// @return Array of authorized addresses.
+    function getAuthorizedAddresses()
+        external
+        view
+        returns (address[] memory)
+    {
+        return authorities;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol
new file mode 100644
index 000000000..7ebd6acf0
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol
@@ -0,0 +1,38 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.23;
+
+// @dev Interface of the asset proxy's assetData.
+// The asset proxies take an ABI encoded `bytes assetData` as argument.
+// This argument is ABI encoded as one of the methods of this interface.
+interface IAssetData {
+    
+    function ERC20Token(address tokenContract)
+        external
+        pure;
+    
+    function ERC721Token(
+        address tokenContract,
+        uint256 tokenId,
+        bytes receiverData
+    )
+        external
+        pure;
+    
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetProxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetProxy.sol
new file mode 100644
index 000000000..eacd5a412
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetProxy.sol
@@ -0,0 +1,47 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "./IAuthorizable.sol";
+
+contract IAssetProxy is
+    IAuthorizable
+{
+
+    /// @dev Transfers assets. Either succeeds or throws.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param from Address to transfer asset from.
+    /// @param to Address to transfer asset to.
+    /// @param amount Amount of asset to transfer.
+    function transferFrom(
+        bytes assetData,
+        address from,
+        address to,
+        uint256 amount
+    )
+        external;
+    
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4);
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAuthorizable.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAuthorizable.sol
new file mode 100644
index 000000000..cedd1744c
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAuthorizable.sol
@@ -0,0 +1,53 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../../utils/Ownable/IOwnable.sol";
+
+contract IAuthorizable is
+    IOwnable
+{
+
+    /// @dev Gets all authorized addresses.
+    /// @return Array of authorized addresses.
+    function getAuthorizedAddresses()
+        external
+        view
+        returns (address[]);
+
+    /// @dev Authorizes an address.
+    /// @param target Address to authorize.
+    function addAuthorizedAddress(address target)
+        external;
+
+    /// @dev Removes authorizion of an address.
+    /// @param target Address to remove authorization from.
+    function removeAuthorizedAddress(address target)
+        external;
+
+    /// @dev Removes authorizion of an address.
+    /// @param target Address to remove authorization from.
+    /// @param index Index of target in authorities array.
+    function removeAuthorizedAddressAtIndex(
+        address target,
+        uint256 index
+    )
+        external;
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/libs/LibAssetProxyErrors.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
new file mode 100644
index 000000000..338cb12e2
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
@@ -0,0 +1,36 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+/// @dev This contract documents the revert reasons used in the AssetProxy contracts.
+/// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
+contract LibAssetProxyErrors {
+
+    /// Authorizable errors ///
+    string constant SENDER_NOT_AUTHORIZED = "SENDER_NOT_AUTHORIZED";                        // Sender not authorized to call this method.
+    string constant TARGET_NOT_AUTHORIZED = "TARGET_NOT_AUTHORIZED";                        // Target address not authorized to call this method.
+    string constant TARGET_ALREADY_AUTHORIZED = "TARGET_ALREADY_AUTHORIZED";                // Target address must not already be authorized.
+    string constant INDEX_OUT_OF_BOUNDS = "INDEX_OUT_OF_BOUNDS";                            // Specified array index is out of bounds.
+    string constant AUTHORIZED_ADDRESS_MISMATCH = "AUTHORIZED_ADDRESS_MISMATCH";            // Address at index does not match given target address.
+
+    /// Transfer errors ///
+    string constant INVALID_AMOUNT = "INVALID_AMOUNT";                                      // Transfer amount must equal 1.
+    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                                    // Transfer failed.
+    string constant LENGTH_GREATER_THAN_131_REQUIRED = "LENGTH_GREATER_THAN_131_REQUIRED";  // Byte array must have a length greater than 0.
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/mixins/MAuthorizable.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/mixins/MAuthorizable.sol
new file mode 100644
index 000000000..6f35bd7ec
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/mixins/MAuthorizable.sol
@@ -0,0 +1,42 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../interfaces/IAuthorizable.sol";
+
+contract MAuthorizable is
+    IAuthorizable
+{
+
+    // Event logged when a new address is authorized.
+    event AuthorizedAddressAdded(
+        address indexed target,
+        address indexed caller
+    );
+
+    // Event logged when a currently authorized address is unauthorized.
+    event AuthorizedAddressRemoved(
+        address indexed target,
+        address indexed caller
+    );
+
+    /// @dev Only authorized addresses can invoke functions with this modifier.
+    modifier onlyAuthorized { revert(); _; }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol b/packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol
new file mode 100644
index 000000000..eb58b3374
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol
@@ -0,0 +1,98 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.10;
+
+import "../../multisig/MultiSigWalletWithTimeLock.sol";
+import "../../utils/LibBytes/LibBytes.sol";
+
+contract AssetProxyOwner is
+    MultiSigWalletWithTimeLock
+{
+    using LibBytes for bytes;
+
+    event AssetProxyRegistration(address assetProxyContract, bool isRegistered);
+
+    // Mapping of AssetProxy contract address =>
+    // if this contract is allowed to call the AssetProxy's `removeAuthorizedAddressAtIndex` method without a time lock.
+    mapping (address => bool) public isAssetProxyRegistered;
+
+    bytes4 constant REMOVE_AUTHORIZED_ADDRESS_AT_INDEX_SELECTOR = bytes4(keccak256("removeAuthorizedAddressAtIndex(address,uint256)"));
+
+    /// @dev Function will revert if the transaction does not call `removeAuthorizedAddressAtIndex`
+    ///      on an approved AssetProxy contract.
+    modifier validRemoveAuthorizedAddressAtIndexTx(uint256 transactionId) {
+        Transaction storage tx = transactions[transactionId];
+        require(isAssetProxyRegistered[tx.destination]);
+        require(tx.data.readBytes4(0) == REMOVE_AUTHORIZED_ADDRESS_AT_INDEX_SELECTOR);
+        _;
+    }
+
+    /// @dev Contract constructor sets initial owners, required number of confirmations,
+    ///      time lock, and list of AssetProxy addresses.
+    /// @param _owners List of initial owners.
+    /// @param _assetProxyContracts Array of AssetProxy contract addresses.
+    /// @param _required Number of required confirmations.
+    /// @param _secondsTimeLocked Duration needed after a transaction is confirmed and before it becomes executable, in seconds.
+    function AssetProxyOwner(
+        address[] memory _owners,
+        address[] memory _assetProxyContracts,
+        uint256 _required,
+        uint256 _secondsTimeLocked
+    )
+        public
+        MultiSigWalletWithTimeLock(_owners, _required, _secondsTimeLocked)
+    {
+        for (uint256 i = 0; i < _assetProxyContracts.length; i++) {
+            address assetProxy = _assetProxyContracts[i];
+            require(assetProxy != address(0));
+            isAssetProxyRegistered[assetProxy] = true;
+        }
+    }
+
+    /// @dev Registers or deregisters an AssetProxy to be able to execute
+    ///      `removeAuthorizedAddressAtIndex` without a timelock.
+    /// @param assetProxyContract Address of AssetProxy contract.
+    /// @param isRegistered Status of approval for AssetProxy contract.
+    function registerAssetProxy(address assetProxyContract, bool isRegistered)
+        public
+        onlyWallet
+        notNull(assetProxyContract)
+    {
+        isAssetProxyRegistered[assetProxyContract] = isRegistered;
+        AssetProxyRegistration(assetProxyContract, isRegistered);
+    }
+
+    /// @dev Allows execution of `removeAuthorizedAddressAtIndex` without time lock.
+    /// @param transactionId Transaction ID.
+    function executeRemoveAuthorizedAddressAtIndex(uint256 transactionId)
+        public
+        notExecuted(transactionId)
+        fullyConfirmed(transactionId)
+        validRemoveAuthorizedAddressAtIndexTx(transactionId)
+    {
+        Transaction storage tx = transactions[transactionId];
+        tx.executed = true;
+        if (tx.destination.call.value(tx.value)(tx.data))
+            Execution(transactionId);
+        else {
+            ExecutionFailure(transactionId);
+            tx.executed = false;
+        }
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/Exchange.sol b/packages/contracts/src/2.0.0/protocol/Exchange/Exchange.sol
new file mode 100644
index 000000000..d36e9633e
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/Exchange.sol
@@ -0,0 +1,52 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "./libs/LibConstants.sol";
+import "./MixinExchangeCore.sol";
+import "./MixinSignatureValidator.sol";
+import "./MixinWrapperFunctions.sol";
+import "./MixinAssetProxyDispatcher.sol";
+import "./MixinTransactions.sol";
+import "./MixinMatchOrders.sol";
+
+contract Exchange is
+    MixinExchangeCore,
+    MixinMatchOrders,
+    MixinSignatureValidator,
+    MixinTransactions,
+    MixinAssetProxyDispatcher,
+    MixinWrapperFunctions
+{
+
+    string constant public VERSION = "2.0.1-alpha";
+
+    // Mixins are instantiated in the order they are inherited
+    constructor (bytes memory _zrxAssetData)
+        public
+        LibConstants(_zrxAssetData) // @TODO: Remove when we deploy.
+        MixinExchangeCore()
+        MixinMatchOrders()
+        MixinSignatureValidator()
+        MixinTransactions()
+        MixinAssetProxyDispatcher()
+        MixinWrapperFunctions()
+    {}
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
new file mode 100644
index 000000000..9e9d88ce7
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
@@ -0,0 +1,175 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../utils/Ownable/Ownable.sol";
+import "../../utils/LibBytes/LibBytes.sol";
+import "./mixins/MAssetProxyDispatcher.sol";
+import "../AssetProxy/interfaces/IAssetProxy.sol";
+
+contract MixinAssetProxyDispatcher is
+    Ownable,
+    MAssetProxyDispatcher
+{
+    using LibBytes for bytes;
+    
+    // Mapping from Asset Proxy Id's to their respective Asset Proxy
+    mapping (bytes4 => IAssetProxy) public assetProxies;
+
+    /// @dev Registers an asset proxy to its asset proxy id.
+    ///      Once an asset proxy is registered, it cannot be unregistered.
+    /// @param assetProxy Address of new asset proxy to register.
+    function registerAssetProxy(address assetProxy)
+        external
+        onlyOwner
+    {
+        IAssetProxy assetProxyContract = IAssetProxy(assetProxy);
+
+        // Ensure that no asset proxy exists with current id.
+        bytes4 assetProxyId = assetProxyContract.getProxyId();
+        address currentAssetProxy = assetProxies[assetProxyId];
+        require(
+            currentAssetProxy == address(0),
+            "ASSET_PROXY_ALREADY_EXISTS"
+        );
+
+        // Add asset proxy and log registration.
+        assetProxies[assetProxyId] = assetProxyContract;
+        emit AssetProxyRegistered(
+            assetProxyId,
+            assetProxy
+        );
+    }
+
+    /// @dev Gets an asset proxy.
+    /// @param assetProxyId Id of the asset proxy.
+    /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered.
+    function getAssetProxy(bytes4 assetProxyId)
+        external
+        view
+        returns (address)
+    {
+        return assetProxies[assetProxyId];
+    }
+
+    /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
+    /// @param assetData Byte array encoded for the asset.
+    /// @param from Address to transfer token from.
+    /// @param to Address to transfer token to.
+    /// @param amount Amount of token to transfer.
+    function dispatchTransferFrom(
+        bytes memory assetData,
+        address from,
+        address to,
+        uint256 amount
+    )
+        internal
+    {
+        // Do nothing if no amount should be transferred.
+        if (amount > 0) {
+            // Ensure assetData length is valid
+            require(
+                assetData.length > 3,
+                "LENGTH_GREATER_THAN_3_REQUIRED"
+            );
+            
+            // Lookup assetProxy
+            bytes4 assetProxyId;
+            assembly {
+                assetProxyId := and(mload(
+                    add(assetData, 32)),
+                    0xFFFFFFFF00000000000000000000000000000000000000000000000000000000
+                )
+            }
+            address assetProxy = assetProxies[assetProxyId];
+
+            // Ensure that assetProxy exists
+            require(
+                assetProxy != address(0),
+                "ASSET_PROXY_DOES_NOT_EXIST"
+            );
+            
+            // We construct calldata for the `assetProxy.transferFrom` ABI.
+            // The layout of this calldata is in the table below.
+            // 
+            // | Area     | Offset | Length  | Contents                                    |
+            // | -------- |--------|---------|-------------------------------------------- |
+            // | Header   | 0      | 4       | function selector                           |
+            // | Params   |        | 4 * 32  | function parameters:                        |
+            // |          | 4      |         |   1. offset to assetData (*)                |
+            // |          | 36     |         |   2. from                                   |
+            // |          | 68     |         |   3. to                                     |
+            // |          | 100    |         |   4. amount                                 |
+            // | Data     |        |         | assetData:                                  |
+            // |          | 132    | 32      | assetData Length                            |
+            // |          | 164    | **      | assetData Contents                          |
+
+            assembly {
+                /////// Setup State ///////
+                // `cdStart` is the start of the calldata for `assetProxy.transferFrom` (equal to free memory ptr).
+                let cdStart := mload(64)
+                // `dataAreaLength` is the total number of words needed to store `assetData`
+                //  As-per the ABI spec, this value is padded up to the nearest multiple of 32,
+                //  and includes 32-bytes for length.
+                let dataAreaLength := and(add(mload(assetData), 63), 0xFFFFFFFFFFFE0)
+                // `cdEnd` is the end of the calldata for `assetProxy.transferFrom`.
+                let cdEnd := add(cdStart, add(132, dataAreaLength))
+
+                
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFromSelector`.
+                // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+                mstore(cdStart, 0xa85e59e400000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // Each parameter is padded to 32-bytes. The entire Params Area is 128 bytes.
+                // Notes:
+                //   1. The offset to `assetData` is the length of the Params Area (128 bytes).
+                //   2. A 20-byte mask is applied to addresses to zero-out the unused bytes.
+                mstore(add(cdStart, 4), 128)
+                mstore(add(cdStart, 36), and(from, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(cdStart, 68), and(to, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(cdStart, 100), amount)
+                
+                /////// Setup Data Area ///////
+                // This area holds `assetData`.
+                let dataArea := add(cdStart, 132)
+                for {} lt(dataArea, cdEnd) {} {
+                    mstore(dataArea, mload(assetData))
+                    dataArea := add(dataArea, 32)
+                    assetData := add(assetData, 32)
+                }
+
+                /////// Call `assetProxy.transferFrom` using the constructed calldata ///////
+                let success := call(
+                    gas,                    // forward all gas
+                    assetProxy,             // call address of asset proxy
+                    0,                      // don't send any ETH
+                    cdStart,                // pointer to start of input
+                    sub(cdEnd, cdStart),    // length of input  
+                    cdStart,                // write output over input
+                    512                     // reserve 512 bytes for output
+                )
+                if iszero(success) {
+                    revert(cdStart, returndatasize())
+                }
+            }
+        }
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
new file mode 100644
index 000000000..c0ed023ac
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
@@ -0,0 +1,436 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "./libs/LibConstants.sol";
+import "./libs/LibFillResults.sol";
+import "./libs/LibOrder.sol";
+import "./libs/LibMath.sol";
+import "./mixins/MExchangeCore.sol";
+import "./mixins/MSignatureValidator.sol";
+import "./mixins/MTransactions.sol";
+import "./mixins/MAssetProxyDispatcher.sol";
+
+contract MixinExchangeCore is
+    LibConstants,
+    LibMath,
+    LibOrder,
+    LibFillResults,
+    MAssetProxyDispatcher,
+    MExchangeCore,
+    MSignatureValidator,
+    MTransactions
+{
+    // Mapping of orderHash => amount of takerAsset already bought by maker
+    mapping (bytes32 => uint256) public filled;
+
+    // Mapping of orderHash => cancelled
+    mapping (bytes32 => bool) public cancelled;
+
+    // Mapping of makerAddress => senderAddress => lowest salt an order can have in order to be fillable
+    // Orders with specified senderAddress and with a salt less than their epoch to are considered cancelled
+    mapping (address => mapping (address => uint256)) public orderEpoch;
+
+    ////// Core exchange functions //////
+
+    /// @dev Cancels all orders created by makerAddress with a salt less than or equal to the targetOrderEpoch
+    ///      and senderAddress equal to msg.sender (or null address if msg.sender == makerAddress).
+    /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
+    function cancelOrdersUpTo(uint256 targetOrderEpoch)
+        external
+    {
+        address makerAddress = getCurrentContextAddress();
+        // If this function is called via `executeTransaction`, we only update the orderEpoch for the makerAddress/msg.sender combination.
+        // This allows external filter contracts to add rules to how orders are cancelled via this function.
+        address senderAddress = makerAddress == msg.sender ? address(0) : msg.sender;
+
+        // orderEpoch is initialized to 0, so to cancelUpTo we need salt + 1
+        uint256 newOrderEpoch = targetOrderEpoch + 1;  
+        uint256 oldOrderEpoch = orderEpoch[makerAddress][senderAddress];
+
+        // Ensure orderEpoch is monotonically increasing
+        require(
+            newOrderEpoch > oldOrderEpoch, 
+            "INVALID_NEW_ORDER_EPOCH"
+        );
+
+        // Update orderEpoch
+        orderEpoch[makerAddress][senderAddress] = newOrderEpoch;
+        emit CancelUpTo(makerAddress, senderAddress, newOrderEpoch);
+    }
+
+    /// @dev Fills the input order.
+    /// @param order Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signature Proof that order has been created by maker.
+    /// @return Amounts filled and fees paid by maker and taker.
+    function fillOrder(
+        Order memory order,
+        uint256 takerAssetFillAmount,
+        bytes memory signature
+    )
+        public
+        returns (FillResults memory fillResults)
+    {
+        // Fetch order info
+        OrderInfo memory orderInfo = getOrderInfo(order);
+
+        // Fetch taker address
+        address takerAddress = getCurrentContextAddress();
+
+        // Get amount of takerAsset to fill
+        uint256 remainingTakerAssetAmount = safeSub(order.takerAssetAmount, orderInfo.orderTakerAssetFilledAmount);
+        uint256 takerAssetFilledAmount = min256(takerAssetFillAmount, remainingTakerAssetAmount);
+
+        // Validate context
+        assertValidFill(
+            order,
+            orderInfo,
+            takerAddress,
+            takerAssetFillAmount,
+            takerAssetFilledAmount,
+            signature
+        );
+
+        // Compute proportional fill amounts
+        fillResults = calculateFillResults(order, takerAssetFilledAmount);
+
+        // Update exchange internal state
+        updateFilledState(
+            order,
+            takerAddress,
+            orderInfo.orderHash,
+            orderInfo.orderTakerAssetFilledAmount,
+            fillResults
+        );
+    
+        // Settle order
+        settleOrder(order, takerAddress, fillResults);
+
+        return fillResults;
+    }
+
+    /// @dev After calling, the order can not be filled anymore.
+    ///      Throws if order is invalid or sender does not have permission to cancel.
+    /// @param order Order to cancel. Order must be OrderStatus.FILLABLE.
+    function cancelOrder(Order memory order)
+        public
+    {
+        // Fetch current order status
+        OrderInfo memory orderInfo = getOrderInfo(order);
+
+        // Validate context
+        assertValidCancel(order, orderInfo);
+
+        // Perform cancel
+        updateCancelledState(order, orderInfo.orderHash);
+    }
+
+    /// @dev Gets information about an order: status, hash, and amount filled.
+    /// @param order Order to gather information on.
+    /// @return OrderInfo Information about the order and its state.
+    ///         See LibOrder.OrderInfo for a complete description.
+    function getOrderInfo(Order memory order)
+        public
+        view
+        returns (OrderInfo memory orderInfo)
+    {
+        // Compute the order hash
+        orderInfo.orderHash = getOrderHash(order);
+
+        // If order.makerAssetAmount is zero, we also reject the order.
+        // While the Exchange contract handles them correctly, they create
+        // edge cases in the supporting infrastructure because they have
+        // an 'infinite' price when computed by a simple division.
+        if (order.makerAssetAmount == 0) {
+            orderInfo.orderStatus = uint8(OrderStatus.INVALID_MAKER_ASSET_AMOUNT);
+            return orderInfo;
+        }
+
+        // If order.takerAssetAmount is zero, then the order will always
+        // be considered filled because 0 == takerAssetAmount == orderTakerAssetFilledAmount
+        // Instead of distinguishing between unfilled and filled zero taker
+        // amount orders, we choose not to support them.
+        if (order.takerAssetAmount == 0) {
+            orderInfo.orderStatus = uint8(OrderStatus.INVALID_TAKER_ASSET_AMOUNT);
+            return orderInfo;
+        }
+
+        // Validate order expiration
+        if (block.timestamp >= order.expirationTimeSeconds) {
+            orderInfo.orderStatus = uint8(OrderStatus.EXPIRED);
+            return orderInfo;
+        }
+
+        // Check if order has been cancelled
+        if (cancelled[orderInfo.orderHash]) {
+            orderInfo.orderStatus = uint8(OrderStatus.CANCELLED);
+            return orderInfo;
+        }
+        if (orderEpoch[order.makerAddress][order.senderAddress] > order.salt) {
+            orderInfo.orderStatus = uint8(OrderStatus.CANCELLED);
+            return orderInfo;
+        }
+
+        // Fetch filled amount and validate order availability
+        orderInfo.orderTakerAssetFilledAmount = filled[orderInfo.orderHash];
+        if (orderInfo.orderTakerAssetFilledAmount >= order.takerAssetAmount) {
+            orderInfo.orderStatus = uint8(OrderStatus.FULLY_FILLED);
+            return orderInfo;
+        }
+
+        // All other statuses are ruled out: order is Fillable
+        orderInfo.orderStatus = uint8(OrderStatus.FILLABLE);
+        return orderInfo;
+    }
+
+    /// @dev Updates state with results of a fill order.
+    /// @param order that was filled.
+    /// @param takerAddress Address of taker who filled the order.
+    /// @param orderTakerAssetFilledAmount Amount of order already filled.
+    /// @return fillResults Amounts filled and fees paid by maker and taker.
+    function updateFilledState(
+        Order memory order,
+        address takerAddress,
+        bytes32 orderHash,
+        uint256 orderTakerAssetFilledAmount,
+        FillResults memory fillResults
+    )
+        internal
+    {
+        // Update state
+        filled[orderHash] = safeAdd(orderTakerAssetFilledAmount, fillResults.takerAssetFilledAmount);
+
+        // Log order
+        emit Fill(
+            order.makerAddress,
+            order.feeRecipientAddress,
+            takerAddress,
+            msg.sender,
+            fillResults.makerAssetFilledAmount,
+            fillResults.takerAssetFilledAmount,
+            fillResults.makerFeePaid,
+            fillResults.takerFeePaid,
+            orderHash,
+            order.makerAssetData,
+            order.takerAssetData
+        );
+    }
+
+    /// @dev Updates state with results of cancelling an order.
+    ///      State is only updated if the order is currently fillable.
+    ///      Otherwise, updating state would have no effect.
+    /// @param order that was cancelled.
+    /// @param orderHash Hash of order that was cancelled.
+    function updateCancelledState(
+        Order memory order,
+        bytes32 orderHash
+    )
+        internal
+    {
+        // Perform cancel
+        cancelled[orderHash] = true;
+
+        // Log cancel
+        emit Cancel(
+            order.makerAddress,
+            order.feeRecipientAddress,
+            msg.sender,
+            orderHash,
+            order.makerAssetData,
+            order.takerAssetData
+        );
+    }
+
+    /// @dev Validates context for fillOrder. Succeeds or throws.
+    /// @param order to be filled.
+    /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
+    /// @param takerAddress Address of order taker.
+    /// @param takerAssetFillAmount Desired amount of order to fill by taker.
+    /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
+    /// @param signature Proof that the orders was created by its maker.
+    function assertValidFill(
+        Order memory order,
+        OrderInfo memory orderInfo,
+        address takerAddress,
+        uint256 takerAssetFillAmount,
+        uint256 takerAssetFilledAmount,
+        bytes memory signature
+    )
+        internal
+        view
+    {
+        // An order can only be filled if its status is FILLABLE.
+        require(
+            orderInfo.orderStatus == uint8(OrderStatus.FILLABLE),
+            "ORDER_UNFILLABLE"
+        );
+
+        // Revert if fill amount is invalid
+        require(
+            takerAssetFillAmount != 0,
+            "INVALID_TAKER_AMOUNT"
+        );
+
+        // Validate sender is allowed to fill this order
+        if (order.senderAddress != address(0)) {
+            require(
+                order.senderAddress == msg.sender,
+                "INVALID_SENDER"
+            );
+        }
+
+        // Validate taker is allowed to fill this order
+        if (order.takerAddress != address(0)) {
+            require(
+                order.takerAddress == takerAddress,
+                "INVALID_TAKER"
+            );
+        }
+
+        // Validate Maker signature (check only if first time seen)
+        if (orderInfo.orderTakerAssetFilledAmount == 0) {
+            require(
+                isValidSignature(
+                    orderInfo.orderHash,
+                    order.makerAddress,
+                    signature
+                ),
+                "INVALID_ORDER_SIGNATURE"
+            );
+        }
+
+        // Validate fill order rounding
+        require(
+            !isRoundingError(
+                takerAssetFilledAmount,
+                order.takerAssetAmount,
+                order.makerAssetAmount
+            ),
+            "ROUNDING_ERROR"
+        );
+    }
+
+    /// @dev Validates context for cancelOrder. Succeeds or throws.
+    /// @param order to be cancelled.
+    /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
+    function assertValidCancel(
+        Order memory order,
+        OrderInfo memory orderInfo
+    )
+        internal
+        view
+    {
+        // Ensure order is valid
+        // An order can only be cancelled if its status is FILLABLE.
+        require(
+            orderInfo.orderStatus == uint8(OrderStatus.FILLABLE),
+            "ORDER_UNFILLABLE"
+        );
+
+        // Validate sender is allowed to cancel this order
+        if (order.senderAddress != address(0)) {
+            require(
+                order.senderAddress == msg.sender,
+                "INVALID_SENDER"
+            );
+        }
+
+        // Validate transaction signed by maker
+        address makerAddress = getCurrentContextAddress();
+        require(
+            order.makerAddress == makerAddress,
+            "INVALID_MAKER"
+        );
+    }
+
+    /// @dev Calculates amounts filled and fees paid by maker and taker.
+    /// @param order to be filled.
+    /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
+    /// @return fillResults Amounts filled and fees paid by maker and taker.
+    function calculateFillResults(
+        Order memory order,
+        uint256 takerAssetFilledAmount
+    )
+        internal
+        pure
+        returns (FillResults memory fillResults)
+    {
+        // Compute proportional transfer amounts
+        // TODO: All three are multiplied by the same fraction. This can
+        // potentially be optimized.
+        fillResults.takerAssetFilledAmount = takerAssetFilledAmount;
+        fillResults.makerAssetFilledAmount = getPartialAmount(
+            fillResults.takerAssetFilledAmount,
+            order.takerAssetAmount,
+            order.makerAssetAmount
+        );
+        fillResults.makerFeePaid = getPartialAmount(
+            fillResults.takerAssetFilledAmount,
+            order.takerAssetAmount,
+            order.makerFee
+        );
+        fillResults.takerFeePaid = getPartialAmount(
+            fillResults.takerAssetFilledAmount,
+            order.takerAssetAmount,
+            order.takerFee
+        );
+
+        return fillResults;
+    }
+
+   /// @dev Settles an order by transferring assets between counterparties.
+    /// @param order Order struct containing order specifications.
+    /// @param takerAddress Address selling takerAsset and buying makerAsset.
+    /// @param fillResults Amounts to be filled and fees paid by maker and taker.
+    function settleOrder(
+        LibOrder.Order memory order,
+        address takerAddress,
+        LibFillResults.FillResults memory fillResults
+    )
+        private
+    {
+        bytes memory zrxAssetData = ZRX_ASSET_DATA;
+        dispatchTransferFrom(
+            order.makerAssetData,
+            order.makerAddress,
+            takerAddress,
+            fillResults.makerAssetFilledAmount
+        );
+        dispatchTransferFrom(
+            order.takerAssetData,
+            takerAddress,
+            order.makerAddress,
+            fillResults.takerAssetFilledAmount
+        );
+        dispatchTransferFrom(
+            zrxAssetData,
+            order.makerAddress,
+            order.feeRecipientAddress,
+            fillResults.makerFeePaid
+        );
+        dispatchTransferFrom(
+            zrxAssetData,
+            takerAddress,
+            order.feeRecipientAddress,
+            fillResults.takerFeePaid
+        );
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
new file mode 100644
index 000000000..1a43eec79
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
@@ -0,0 +1,301 @@
+/*
+  Copyright 2018 ZeroEx Intl.
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "./libs/LibConstants.sol";
+import "./libs/LibMath.sol";
+import "./libs/LibOrder.sol";
+import "./libs/LibFillResults.sol";
+import "./mixins/MExchangeCore.sol";
+import "./mixins/MMatchOrders.sol";
+import "./mixins/MTransactions.sol";
+import "./mixins/MAssetProxyDispatcher.sol";
+
+contract MixinMatchOrders is
+    LibConstants,
+    LibMath,
+    MAssetProxyDispatcher,
+    MExchangeCore,
+    MMatchOrders,
+    MTransactions
+{
+    /// @dev Match two complementary orders that have a profitable spread.
+    ///      Each order is filled at their respective price point. However, the calculations are
+    ///      carried out as though the orders are both being filled at the right order's price point.
+    ///      The profit made by the left order goes to the taker (who matched the two orders).
+    /// @param leftOrder First order to match.
+    /// @param rightOrder Second order to match.
+    /// @param leftSignature Proof that order was created by the left maker.
+    /// @param rightSignature Proof that order was created by the right maker.
+    /// @return matchedFillResults Amounts filled and fees paid by maker and taker of matched orders.
+    /// TODO: Make this function external once supported by Solidity (See Solidity Issues #3199, #1603)
+    function matchOrders(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder,
+        bytes memory leftSignature,
+        bytes memory rightSignature
+    )
+        public
+        returns (LibFillResults.MatchedFillResults memory matchedFillResults)
+    {
+        // We assume that rightOrder.takerAssetData == leftOrder.makerAssetData and rightOrder.makerAssetData == leftOrder.takerAssetData.
+        // If this assumption isn't true, the match will fail at signature validation.
+        rightOrder.makerAssetData = leftOrder.takerAssetData;
+        rightOrder.takerAssetData = leftOrder.makerAssetData;
+
+        // Get left & right order info
+        LibOrder.OrderInfo memory leftOrderInfo = getOrderInfo(leftOrder);
+        LibOrder.OrderInfo memory rightOrderInfo = getOrderInfo(rightOrder);
+
+        // Fetch taker address
+        address takerAddress = getCurrentContextAddress();
+
+        // Either our context is valid or we revert
+        assertValidMatch(leftOrder, rightOrder);
+
+        // Compute proportional fill amounts
+        matchedFillResults = calculateMatchedFillResults(
+            leftOrder,
+            rightOrder,
+            leftOrderInfo.orderTakerAssetFilledAmount,
+            rightOrderInfo.orderTakerAssetFilledAmount
+        );
+
+        // Validate fill contexts
+        assertValidFill(
+            leftOrder,
+            leftOrderInfo,
+            takerAddress,
+            matchedFillResults.left.takerAssetFilledAmount,
+            matchedFillResults.left.takerAssetFilledAmount,
+            leftSignature
+        );
+        assertValidFill(
+            rightOrder,
+            rightOrderInfo,
+            takerAddress,
+            matchedFillResults.right.takerAssetFilledAmount,
+            matchedFillResults.right.takerAssetFilledAmount,
+            rightSignature
+        );
+
+        // Update exchange state
+        updateFilledState(
+            leftOrder,
+            takerAddress,
+            leftOrderInfo.orderHash,
+            leftOrderInfo.orderTakerAssetFilledAmount,
+            matchedFillResults.left
+        );
+        updateFilledState(
+            rightOrder,
+            takerAddress,
+            rightOrderInfo.orderHash,
+            rightOrderInfo.orderTakerAssetFilledAmount,
+            matchedFillResults.right
+        );
+    
+        // Settle matched orders. Succeeds or throws.
+        settleMatchedOrders(
+            leftOrder,
+            rightOrder,
+            takerAddress,
+            matchedFillResults
+        );
+
+        return matchedFillResults;
+    }
+
+    /// @dev Validates context for matchOrders. Succeeds or throws.
+    /// @param leftOrder First order to match.
+    /// @param rightOrder Second order to match.
+    function assertValidMatch(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder
+    )
+        internal
+        pure
+    {
+        // Make sure there is a profitable spread.
+        // There is a profitable spread iff the cost per unit bought (OrderA.MakerAmount/OrderA.TakerAmount) for each order is greater
+        // than the profit per unit sold of the matched order (OrderB.TakerAmount/OrderB.MakerAmount).
+        // This is satisfied by the equations below:
+        // <leftOrder.makerAssetAmount> / <leftOrder.takerAssetAmount> >= <rightOrder.takerAssetAmount> / <rightOrder.makerAssetAmount>
+        // AND
+        // <rightOrder.makerAssetAmount> / <rightOrder.takerAssetAmount> >= <leftOrder.takerAssetAmount> / <leftOrder.makerAssetAmount>
+        // These equations can be combined to get the following:
+        require(
+            safeMul(leftOrder.makerAssetAmount, rightOrder.makerAssetAmount) >=
+            safeMul(leftOrder.takerAssetAmount, rightOrder.takerAssetAmount),
+            "NEGATIVE_SPREAD_REQUIRED"
+        );
+    }
+
+    /// @dev Calculates fill amounts for the matched orders.
+    ///      Each order is filled at their respective price point. However, the calculations are
+    ///      carried out as though the orders are both being filled at the right order's price point.
+    ///      The profit made by the leftOrder order goes to the taker (who matched the two orders).
+    /// @param leftOrder First order to match.
+    /// @param rightOrder Second order to match.
+    /// @param leftOrderTakerAssetFilledAmount Amount of left order already filled.
+    /// @param rightOrderTakerAssetFilledAmount Amount of right order already filled.
+    /// @param matchedFillResults Amounts to fill and fees to pay by maker and taker of matched orders.
+    function calculateMatchedFillResults(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder,
+        uint256 leftOrderTakerAssetFilledAmount,
+        uint256 rightOrderTakerAssetFilledAmount
+    )
+        internal
+        pure
+        returns (LibFillResults.MatchedFillResults memory matchedFillResults)
+    {
+        // We settle orders at the exchange rate of the right order.
+        // The amount saved by the left maker goes to the taker.
+        // Either the left or right order will be fully filled; possibly both.
+        // The left order is fully filled iff the right order can sell more than left can buy.
+        // That is: the amount required to fill the left order is less than or equal to
+        //          the amount we can spend from the right order:
+        //          <leftTakerAssetAmountRemaining> <= <rightTakerAssetAmountRemaining> * <rightMakerToTakerRatio>
+        //          <leftTakerAssetAmountRemaining> <= <rightTakerAssetAmountRemaining> * <rightOrder.makerAssetAmount> / <rightOrder.takerAssetAmount>
+        //          <leftTakerAssetAmountRemaining> * <rightOrder.takerAssetAmount> <= <rightTakerAssetAmountRemaining> * <rightOrder.makerAssetAmount>
+        uint256 leftTakerAssetAmountRemaining = safeSub(leftOrder.takerAssetAmount, leftOrderTakerAssetFilledAmount);
+        uint256 rightTakerAssetAmountRemaining = safeSub(rightOrder.takerAssetAmount, rightOrderTakerAssetFilledAmount);
+        uint256 leftTakerAssetFilledAmount;
+        uint256 rightTakerAssetFilledAmount;
+        if (
+            safeMul(leftTakerAssetAmountRemaining, rightOrder.takerAssetAmount) <=
+            safeMul(rightTakerAssetAmountRemaining, rightOrder.makerAssetAmount)
+        ) {
+            // Left order will be fully filled: maximally fill left
+            leftTakerAssetFilledAmount = leftTakerAssetAmountRemaining;
+
+            // The right order receives an amount proportional to how much was spent.
+            // TODO: Can we ensure rounding error is in the correct direction?
+            rightTakerAssetFilledAmount = getPartialAmount(
+                rightOrder.takerAssetAmount,
+                rightOrder.makerAssetAmount,
+                leftTakerAssetFilledAmount
+            );
+        } else {
+            // Right order will be fully filled: maximally fill right
+            rightTakerAssetFilledAmount = rightTakerAssetAmountRemaining;
+
+            // The left order receives an amount proportional to how much was spent.
+            // TODO: Can we ensure rounding error is in the correct direction?
+            leftTakerAssetFilledAmount = getPartialAmount(
+                rightOrder.makerAssetAmount,
+                rightOrder.takerAssetAmount,
+                rightTakerAssetFilledAmount
+            );
+        }
+
+        // Calculate fill results for left order
+        matchedFillResults.left = calculateFillResults(
+            leftOrder,
+            leftTakerAssetFilledAmount
+        );
+
+        // Calculate fill results for right order
+        matchedFillResults.right = calculateFillResults(
+            rightOrder,
+            rightTakerAssetFilledAmount
+        );
+
+        // Calculate amount given to taker
+        matchedFillResults.leftMakerAssetSpreadAmount = safeSub(
+            matchedFillResults.left.makerAssetFilledAmount,
+            matchedFillResults.right.takerAssetFilledAmount
+        );
+
+        // Return fill results
+        return matchedFillResults;
+    }
+
+    /// @dev Settles matched order by transferring appropriate funds between order makers, taker, and fee recipient.
+    /// @param leftOrder First matched order.
+    /// @param rightOrder Second matched order.
+    /// @param takerAddress Address that matched the orders. The taker receives the spread between orders as profit.
+    /// @param matchedFillResults Struct holding amounts to transfer between makers, taker, and fee recipients.
+    function settleMatchedOrders(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder,
+        address takerAddress,
+        LibFillResults.MatchedFillResults memory matchedFillResults
+    )
+        private
+    {
+        bytes memory zrxAssetData = ZRX_ASSET_DATA;
+        // Order makers and taker
+        dispatchTransferFrom(
+            leftOrder.makerAssetData,
+            leftOrder.makerAddress,
+            rightOrder.makerAddress,
+            matchedFillResults.right.takerAssetFilledAmount
+        );
+        dispatchTransferFrom(
+            rightOrder.makerAssetData,
+            rightOrder.makerAddress,
+            leftOrder.makerAddress,
+            matchedFillResults.left.takerAssetFilledAmount
+        );
+        dispatchTransferFrom(
+            leftOrder.makerAssetData,
+            leftOrder.makerAddress,
+            takerAddress,
+            matchedFillResults.leftMakerAssetSpreadAmount
+        );
+
+        // Maker fees
+        dispatchTransferFrom(
+            zrxAssetData,
+            leftOrder.makerAddress,
+            leftOrder.feeRecipientAddress,
+            matchedFillResults.left.makerFeePaid
+        );
+        dispatchTransferFrom(
+            zrxAssetData,
+            rightOrder.makerAddress,
+            rightOrder.feeRecipientAddress,
+            matchedFillResults.right.makerFeePaid
+        );
+
+        // Taker fees
+        if (leftOrder.feeRecipientAddress == rightOrder.feeRecipientAddress) {
+            dispatchTransferFrom(
+                zrxAssetData,
+                takerAddress,
+                leftOrder.feeRecipientAddress,
+                safeAdd(
+                    matchedFillResults.left.takerFeePaid,
+                    matchedFillResults.right.takerFeePaid
+                )
+            );
+        } else {
+            dispatchTransferFrom(
+                zrxAssetData,
+                takerAddress,
+                leftOrder.feeRecipientAddress,
+                matchedFillResults.left.takerFeePaid
+            );
+            dispatchTransferFrom(
+                zrxAssetData,
+                takerAddress,
+                rightOrder.feeRecipientAddress,
+                matchedFillResults.right.takerFeePaid
+            );
+        }
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
new file mode 100644
index 000000000..29172057a
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
@@ -0,0 +1,255 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../utils/LibBytes/LibBytes.sol";
+import "./mixins/MSignatureValidator.sol";
+import "./mixins/MTransactions.sol";
+import "./interfaces/IWallet.sol";
+import "./interfaces/IValidator.sol";
+
+contract MixinSignatureValidator is
+    MSignatureValidator,
+    MTransactions
+{
+    using LibBytes for bytes;
+    
+    // Mapping of hash => signer => signed
+    mapping (bytes32 => mapping (address => bool)) public preSigned;
+
+    // Mapping of signer => validator => approved
+    mapping (address => mapping (address => bool)) public allowedValidators;
+
+    /// @dev Approves a hash on-chain using any valid signature type.
+    ///      After presigning a hash, the preSign signature type will become valid for that hash and signer.
+    /// @param signerAddress Address that should have signed the given hash.
+    /// @param signature Proof that the hash has been signed by signer.
+    function preSign(
+        bytes32 hash,
+        address signerAddress,
+        bytes signature
+    )
+        external
+    {
+        require(
+            isValidSignature(
+                hash,
+                signerAddress,
+                signature
+            ),
+            "INVALID_SIGNATURE"
+        );
+        preSigned[hash][signerAddress] = true;
+    }
+
+    /// @dev Approves/unnapproves a Validator contract to verify signatures on signer's behalf.
+    /// @param validatorAddress Address of Validator contract.
+    /// @param approval Approval or disapproval of  Validator contract.
+    function setSignatureValidatorApproval(
+        address validatorAddress,
+        bool approval
+    )
+        external
+    {
+        address signerAddress = getCurrentContextAddress();
+        allowedValidators[signerAddress][validatorAddress] = approval;
+        emit SignatureValidatorApproval(
+            signerAddress,
+            validatorAddress,
+            approval
+        );
+    }
+
+    /// @dev Verifies that a hash has been signed by the given signer.
+    /// @param hash Any 32 byte hash.
+    /// @param signerAddress Address that should have signed the given hash.
+    /// @param signature Proof that the hash has been signed by signer.
+    /// @return True if the address recovered from the provided signature matches the input signer address.
+    function isValidSignature(
+        bytes32 hash,
+        address signerAddress,
+        bytes memory signature
+    )
+        public
+        view
+        returns (bool isValid)
+    {
+        // TODO: Domain separation: make hash depend on role. (Taker sig should not be valid as maker sig, etc.)
+        require(
+            signature.length > 0,
+            "LENGTH_GREATER_THAN_0_REQUIRED"
+        );
+
+        // Ensure signature is supported
+        uint8 signatureTypeRaw = uint8(signature.popLastByte());
+        require(
+            signatureTypeRaw < uint8(SignatureType.NSignatureTypes),
+            "SIGNATURE_UNSUPPORTED"
+        );
+
+        // Pop last byte off of signature byte array.
+        SignatureType signatureType = SignatureType(signatureTypeRaw);
+
+        // Variables are not scoped in Solidity.
+        uint8 v;
+        bytes32 r;
+        bytes32 s;
+        address recovered;
+
+        // Always illegal signature.
+        // This is always an implicit option since a signer can create a
+        // signature array with invalid type or length. We may as well make
+        // it an explicit option. This aids testing and analysis. It is
+        // also the initialization value for the enum type.
+        if (signatureType == SignatureType.Illegal) {
+            revert("SIGNATURE_ILLEGAL");
+
+        // Always invalid signature.
+        // Like Illegal, this is always implicitly available and therefore
+        // offered explicitly. It can be implicitly created by providing
+        // a correctly formatted but incorrect signature.
+        } else if (signatureType == SignatureType.Invalid) {
+            require(
+                signature.length == 0,
+                "LENGTH_0_REQUIRED"
+            );
+            isValid = false;
+            return isValid;
+
+        // Signature using EIP712
+        } else if (signatureType == SignatureType.EIP712) {
+            require(
+                signature.length == 65,
+                "LENGTH_65_REQUIRED"
+            );
+            v = uint8(signature[0]);
+            r = signature.readBytes32(1);
+            s = signature.readBytes32(33);
+            recovered = ecrecover(hash, v, r, s);
+            isValid = signerAddress == recovered;
+            return isValid;
+
+        // Signed using web3.eth_sign
+        } else if (signatureType == SignatureType.EthSign) {
+            require(
+                signature.length == 65,
+                "LENGTH_65_REQUIRED"
+            );
+            v = uint8(signature[0]);
+            r = signature.readBytes32(1);
+            s = signature.readBytes32(33);
+            recovered = ecrecover(
+                keccak256(abi.encodePacked(
+                    "\x19Ethereum Signed Message:\n32",
+                    hash
+                )),
+                v,
+                r,
+                s
+            );
+            isValid = signerAddress == recovered;
+            return isValid;
+
+        // Implicitly signed by caller.
+        // The signer has initiated the call. In the case of non-contract
+        // accounts it means the transaction itself was signed.
+        // Example: let's say for a particular operation three signatures
+        // A, B and C are required. To submit the transaction, A and B can
+        // give a signature to C, who can then submit the transaction using
+        // `Caller` for his own signature. Or A and C can sign and B can
+        // submit using `Caller`. Having `Caller` allows this flexibility.
+        } else if (signatureType == SignatureType.Caller) {
+            require(
+                signature.length == 0,
+                "LENGTH_0_REQUIRED"
+            );
+            isValid = signerAddress == msg.sender;
+            return isValid;
+
+        // Signature verified by wallet contract.
+        // If used with an order, the maker of the order is the wallet contract.
+        } else if (signatureType == SignatureType.Wallet) {
+            isValid = IWallet(signerAddress).isValidSignature(hash, signature);
+            return isValid;
+
+        // Signature verified by validator contract.
+        // If used with an order, the maker of the order can still be an EOA.
+        // A signature using this type should be encoded as:
+        // | Offset   | Length | Contents                        |
+        // | 0x00     | x      | Signature to validate           |
+        // | 0x00 + x | 20     | Address of validator contract   |
+        // | 0x14 + x | 1      | Signature type is always "\x06" |
+        } else if (signatureType == SignatureType.Validator) {
+            // Pop last 20 bytes off of signature byte array.
+
+            address validatorAddress = signature.popLast20Bytes();
+            
+            // Ensure signer has approved validator.
+            if (!allowedValidators[signerAddress][validatorAddress]) {
+                return false;
+            }
+            isValid = IValidator(validatorAddress).isValidSignature(
+                hash,
+                signerAddress,
+                signature
+            );
+            return isValid;
+
+        // Signer signed hash previously using the preSign function.
+        } else if (signatureType == SignatureType.PreSigned) {
+            isValid = preSigned[hash][signerAddress];
+            return isValid;
+
+        // Signature from Trezor hardware wallet.
+        // It differs from web3.eth_sign in the encoding of message length
+        // (Bitcoin varint encoding vs ascii-decimal, the latter is not
+        // self-terminating which leads to ambiguities).
+        // See also:
+        // https://en.bitcoin.it/wiki/Protocol_documentation#Variable_length_integer
+        // https://github.com/trezor/trezor-mcu/blob/master/firmware/ethereum.c#L602
+        // https://github.com/trezor/trezor-mcu/blob/master/firmware/crypto.c#L36
+        } else if (signatureType == SignatureType.Trezor) {
+            require(
+                signature.length == 65,
+                "LENGTH_65_REQUIRED"
+            );
+            v = uint8(signature[0]);
+            r = signature.readBytes32(1);
+            s = signature.readBytes32(33);
+            recovered = ecrecover(
+                keccak256(abi.encodePacked(
+                    "\x19Ethereum Signed Message:\n\x20",
+                    hash
+                )),
+                v,
+                r,
+                s
+            );
+            isValid = signerAddress == recovered;
+            return isValid;
+        }
+
+        // Anything else is illegal (We do not return false because
+        // the signature may actually be valid, just not in a format
+        // that we currently support. In this case returning false
+        // may lead the caller to incorrectly believe that the
+        // signature was invalid.)
+        revert("SIGNATURE_UNSUPPORTED");
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
new file mode 100644
index 000000000..31f7f2847
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
@@ -0,0 +1,154 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+pragma solidity ^0.4.24;
+
+import "./libs/LibExchangeErrors.sol";
+import "./mixins/MSignatureValidator.sol";
+import "./mixins/MTransactions.sol";
+import "./libs/LibEIP712.sol";
+
+contract MixinTransactions is
+    LibEIP712,
+    MSignatureValidator,
+    MTransactions
+{
+
+    // Mapping of transaction hash => executed
+    // This prevents transactions from being executed more than once.
+    mapping (bytes32 => bool) public transactions;
+
+    // Address of current transaction signer
+    address public currentContextAddress;
+
+    // Hash for the EIP712 ZeroEx Transaction Schema
+    bytes32 constant EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH = keccak256(abi.encodePacked(
+        "ZeroExTransaction(",
+        "uint256 salt,",
+        "address signerAddress,",
+        "bytes data",
+        ")"
+    ));
+
+    /// @dev Calculates EIP712 hash of the Transaction.
+    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
+    /// @param signerAddress Address of transaction signer.
+    /// @param data AbiV2 encoded calldata.
+    /// @return EIP712 hash of the Transaction.
+    function hashZeroExTransaction(
+        uint256 salt,
+        address signerAddress,
+        bytes memory data
+    )
+        internal
+        pure
+        returns (bytes32 result)
+    {
+        bytes32 schemaHash = EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH;
+        bytes32 dataHash = keccak256(data);
+        // Assembly for more efficiently computing:
+        // keccak256(abi.encode(
+        //   EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH,
+        //   salt,
+        //   signerAddress,
+        //   keccak256(data)
+        //  ));
+        assembly {
+            let memPtr := mload(64)
+            mstore(memPtr, schemaHash)
+            mstore(add(memPtr, 32), salt)
+            mstore(add(memPtr, 64), and(signerAddress, 0xffffffffffffffffffffffffffffffffffffffff))
+            mstore(add(memPtr, 96), dataHash)
+            result := keccak256(memPtr, 128)
+        }
+
+        return result;
+    }
+
+    /// @dev Executes an exchange method call in the context of signer.
+    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
+    /// @param signerAddress Address of transaction signer.
+    /// @param data AbiV2 encoded calldata.
+    /// @param signature Proof of signer transaction by signer.
+    function executeTransaction(
+        uint256 salt,
+        address signerAddress,
+        bytes data,
+        bytes signature
+    )
+        external
+    {
+        // Prevent reentrancy
+        require(
+            currentContextAddress == address(0),
+            "REENTRANCY_ILLEGAL"
+        );
+
+        bytes32 transactionHash = hashEIP712Message(hashZeroExTransaction(
+            salt,
+            signerAddress,
+            data
+        ));
+
+        // Validate transaction has not been executed
+        require(
+            !transactions[transactionHash],
+            "INVALID_TX_HASH"
+        );
+
+        // Transaction always valid if signer is sender of transaction
+        if (signerAddress != msg.sender) {
+            // Validate signature
+            require(
+                isValidSignature(
+                    transactionHash,
+                    signerAddress,
+                    signature
+                ),
+                "INVALID_TX_SIGNATURE"
+            );
+
+            // Set the current transaction signer
+            currentContextAddress = signerAddress;
+        }
+
+        // Execute transaction
+        transactions[transactionHash] = true;
+        require(
+            address(this).delegatecall(data),
+            "FAILED_EXECUTION"
+        );
+
+        // Reset current transaction signer
+        // TODO: Check if gas is paid when currentContextAddress is already 0.
+        currentContextAddress = address(0);
+    }
+
+    /// @dev The current function will be called in the context of this address (either 0x transaction signer or `msg.sender`).
+    ///      If calling a fill function, this address will represent the taker.
+    ///      If calling a cancel function, this address will represent the maker.
+    /// @return Signer of 0x transaction if entry point is `executeTransaction`.
+    ///         `msg.sender` if entry point is any other function.
+    function getCurrentContextAddress()
+        internal
+        view
+        returns (address)
+    {
+        address contextAddress = currentContextAddress == address(0) ? msg.sender : currentContextAddress;
+        return contextAddress;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
new file mode 100644
index 000000000..00668ca43
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
@@ -0,0 +1,531 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "./libs/LibMath.sol";
+import "./libs/LibOrder.sol";
+import "./libs/LibFillResults.sol";
+import "./mixins/MExchangeCore.sol";
+
+contract MixinWrapperFunctions is
+    LibMath,
+    LibFillResults,
+    MExchangeCore
+{
+    /// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
+    /// @param order Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signature Proof that order has been created by maker.
+    function fillOrKillOrder(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount,
+        bytes memory signature
+    )
+        public
+        returns (FillResults memory fillResults)
+    {
+        fillResults = fillOrder(
+            order,
+            takerAssetFillAmount,
+            signature
+        );
+        require(
+            fillResults.takerAssetFilledAmount == takerAssetFillAmount,
+            "COMPLETE_FILL_FAILED"
+        );
+        return fillResults;
+    }
+
+    /// @dev Fills an order with specified parameters and ECDSA signature.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param order Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signature Proof that order has been created by maker.
+    /// @return Amounts filled and fees paid by maker and taker.
+    function fillOrderNoThrow(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount,
+        bytes memory signature
+    )
+        public
+        returns (FillResults memory fillResults)
+    {
+        // We need to call MExchangeCore.fillOrder using a delegatecall in
+        // assembly so that we can intercept a call that throws. For this, we
+        // need the input encoded in memory in the Ethereum ABIv2 format [1].
+
+        // | Area     | Offset | Length  | Contents                                    |
+        // | -------- |--------|---------|-------------------------------------------- |
+        // | Header   | 0x00   | 4       | function selector                           |
+        // | Params   |        | 3 * 32  | function parameters:                        |
+        // |          | 0x00   |         |   1. offset to order (*)                    |
+        // |          | 0x20   |         |   2. takerAssetFillAmount                   |
+        // |          | 0x40   |         |   3. offset to signature (*)                |
+        // | Data     |        | 12 * 32 | order:                                      |
+        // |          | 0x000  |         |   1.  senderAddress                         |
+        // |          | 0x020  |         |   2.  makerAddress                          |
+        // |          | 0x040  |         |   3.  takerAddress                          |
+        // |          | 0x060  |         |   4.  feeRecipientAddress                   |
+        // |          | 0x080  |         |   5.  makerAssetAmount                      |
+        // |          | 0x0A0  |         |   6.  takerAssetAmount                      |
+        // |          | 0x0C0  |         |   7.  makerFeeAmount                        |
+        // |          | 0x0E0  |         |   8.  takerFeeAmount                        |
+        // |          | 0x100  |         |   9.  expirationTimeSeconds                 |
+        // |          | 0x120  |         |   10. salt                                  |
+        // |          | 0x140  |         |   11. Offset to makerAssetData (*)          |
+        // |          | 0x160  |         |   12. Offset to takerAssetData (*)          |
+        // |          | 0x180  | 32      | makerAssetData Length                       |
+        // |          | 0x1A0  | **      | makerAssetData Contents                     |
+        // |          | 0x1C0  | 32      | takerAssetData Length                       |
+        // |          | 0x1E0  | **      | takerAssetData Contents                     |
+        // |          | 0x200  | 32      | signature Length                            |
+        // |          | 0x220  | **      | signature Contents                          |
+
+        // * Offsets are calculated from the beginning of the current area: Header, Params, Data:
+        //     An offset stored in the Params area is calculated from the beginning of the Params section.
+        //     An offset stored in the Data area is calculated from the beginning of the Data section.
+
+        // ** The length of dynamic array contents are stored in the field immediately preceeding the contents.
+
+        // [1]: https://solidity.readthedocs.io/en/develop/abi-spec.html
+
+        bytes4 fillOrderSelector = this.fillOrder.selector;
+
+        assembly {
+
+            // Areas below may use the following variables:
+            //   1. <area>Start   -- Start of this area in memory
+            //   2. <area>End     -- End of this area in memory. This value may
+            //                       be precomputed (before writing contents),
+            //                       or it may be computed as contents are written.
+            //   3. <area>Offset  -- Current offset into area. If an area's End
+            //                       is precomputed, this variable tracks the
+            //                       offsets of contents as they are written.
+
+            /////// Setup Header Area ///////
+            // Load free memory pointer
+            let headerAreaStart := mload(0x40)
+            mstore(headerAreaStart, fillOrderSelector)
+            let headerAreaEnd := add(headerAreaStart, 0x4)
+
+            /////// Setup Params Area ///////
+            // This area is preallocated and written to later.
+            // This is because we need to fill in offsets that have not yet been calculated.
+            let paramsAreaStart := headerAreaEnd
+            let paramsAreaEnd := add(paramsAreaStart, 0x60)
+            let paramsAreaOffset := paramsAreaStart
+
+            /////// Setup Data Area ///////
+            let dataAreaStart := paramsAreaEnd
+            let dataAreaEnd := dataAreaStart
+
+            // Offset from the source data we're reading from
+            let sourceOffset := order
+            // arrayLenBytes and arrayLenWords track the length of a dynamically-allocated bytes array.
+            let arrayLenBytes := 0
+            let arrayLenWords := 0
+
+            /////// Write order Struct ///////
+            // Write memory location of Order, relative to the start of the
+            // parameter list, then increment the paramsAreaOffset respectively.
+            mstore(paramsAreaOffset, sub(dataAreaEnd, paramsAreaStart))
+            paramsAreaOffset := add(paramsAreaOffset, 0x20)
+
+            // Write values for each field in the order
+            // It would be nice to use a loop, but we save on gas by writing
+            // the stores sequentially.
+            mstore(dataAreaEnd, mload(sourceOffset))                            // makerAddress
+            mstore(add(dataAreaEnd, 0x20), mload(add(sourceOffset, 0x20)))      // takerAddress
+            mstore(add(dataAreaEnd, 0x40), mload(add(sourceOffset, 0x40)))      // feeRecipientAddress
+            mstore(add(dataAreaEnd, 0x60), mload(add(sourceOffset, 0x60)))      // senderAddress
+            mstore(add(dataAreaEnd, 0x80), mload(add(sourceOffset, 0x80)))      // makerAssetAmount
+            mstore(add(dataAreaEnd, 0xA0), mload(add(sourceOffset, 0xA0)))      // takerAssetAmount
+            mstore(add(dataAreaEnd, 0xC0), mload(add(sourceOffset, 0xC0)))      // makerFeeAmount
+            mstore(add(dataAreaEnd, 0xE0), mload(add(sourceOffset, 0xE0)))      // takerFeeAmount
+            mstore(add(dataAreaEnd, 0x100), mload(add(sourceOffset, 0x100)))    // expirationTimeSeconds
+            mstore(add(dataAreaEnd, 0x120), mload(add(sourceOffset, 0x120)))    // salt
+            mstore(add(dataAreaEnd, 0x140), mload(add(sourceOffset, 0x140)))    // Offset to makerAssetData
+            mstore(add(dataAreaEnd, 0x160), mload(add(sourceOffset, 0x160)))    // Offset to takerAssetData
+            dataAreaEnd := add(dataAreaEnd, 0x180)
+            sourceOffset := add(sourceOffset, 0x180)
+
+            // Write offset to <order.makerAssetData>
+            mstore(add(dataAreaStart, mul(10, 0x20)), sub(dataAreaEnd, dataAreaStart))
+
+            // Calculate length of <order.makerAssetData>
+            sourceOffset := mload(add(order, 0x140)) // makerAssetData
+            arrayLenBytes := mload(sourceOffset)
+            sourceOffset := add(sourceOffset, 0x20)
+            arrayLenWords := div(add(arrayLenBytes, 0x1F), 0x20)
+
+            // Write length of <order.makerAssetData>
+            mstore(dataAreaEnd, arrayLenBytes)
+            dataAreaEnd := add(dataAreaEnd, 0x20)
+
+            // Write contents of <order.makerAssetData>
+            for {let i := 0} lt(i, arrayLenWords) {i := add(i, 1)} {
+                mstore(dataAreaEnd, mload(sourceOffset))
+                dataAreaEnd := add(dataAreaEnd, 0x20)
+                sourceOffset := add(sourceOffset, 0x20)
+            }
+
+            // Write offset to <order.takerAssetData>
+            mstore(add(dataAreaStart, mul(11, 0x20)), sub(dataAreaEnd, dataAreaStart))
+
+            // Calculate length of <order.takerAssetData>
+            sourceOffset := mload(add(order, 0x160)) // takerAssetData
+            arrayLenBytes := mload(sourceOffset)
+            sourceOffset := add(sourceOffset, 0x20)
+            arrayLenWords := div(add(arrayLenBytes, 0x1F), 0x20)
+
+            // Write length of <order.takerAssetData>
+            mstore(dataAreaEnd, arrayLenBytes)
+            dataAreaEnd := add(dataAreaEnd, 0x20)
+
+            // Write contents of  <order.takerAssetData>
+            for {let i := 0} lt(i, arrayLenWords) {i := add(i, 1)} {
+                mstore(dataAreaEnd, mload(sourceOffset))
+                dataAreaEnd := add(dataAreaEnd, 0x20)
+                sourceOffset := add(sourceOffset, 0x20)
+            }
+
+            /////// Write takerAssetFillAmount ///////
+            mstore(paramsAreaOffset, takerAssetFillAmount)
+            paramsAreaOffset := add(paramsAreaOffset, 0x20)
+
+            /////// Write signature ///////
+            // Write offset to paramsArea
+            mstore(paramsAreaOffset, sub(dataAreaEnd, paramsAreaStart))
+
+            // Calculate length of signature
+            sourceOffset := signature
+            arrayLenBytes := mload(sourceOffset)
+            sourceOffset := add(sourceOffset, 0x20)
+            arrayLenWords := div(add(arrayLenBytes, 0x1F), 0x20)
+
+            // Write length of signature
+            mstore(dataAreaEnd, arrayLenBytes)
+            dataAreaEnd := add(dataAreaEnd, 0x20)
+
+            // Write contents of signature
+            for {let i := 0} lt(i, arrayLenWords) {i := add(i, 1)} {
+                mstore(dataAreaEnd, mload(sourceOffset))
+                dataAreaEnd := add(dataAreaEnd, 0x20)
+                sourceOffset := add(sourceOffset, 0x20)
+            }
+
+            // Execute delegatecall
+            let success := delegatecall(
+                gas,                                // forward all gas, TODO: look into gas consumption of assert/throw
+                address,                            // call address of this contract
+                headerAreaStart,                    // pointer to start of input
+                sub(dataAreaEnd, headerAreaStart),  // length of input
+                headerAreaStart,                    // write output over input
+                128                                 // output size is 128 bytes
+            )
+            switch success
+            case 0 {
+                mstore(fillResults, 0)
+                mstore(add(fillResults, 32), 0)
+                mstore(add(fillResults, 64), 0)
+                mstore(add(fillResults, 96), 0)
+            }
+            case 1 {
+                mstore(fillResults, mload(headerAreaStart))
+                mstore(add(fillResults, 32), mload(add(headerAreaStart, 32)))
+                mstore(add(fillResults, 64), mload(add(headerAreaStart, 64)))
+                mstore(add(fillResults, 96), mload(add(headerAreaStart, 96)))
+            }
+        }
+        return fillResults;
+    }
+
+    /// @dev Synchronously executes multiple calls of fillOrder.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    ///         NOTE: makerAssetFilledAmount and takerAssetFilledAmount may include amounts filled of different assets.
+    function batchFillOrders(
+        LibOrder.Order[] memory orders,
+        uint256[] memory takerAssetFillAmounts,
+        bytes[] memory signatures
+    )
+        public
+        returns (FillResults memory totalFillResults)
+    {
+        for (uint256 i = 0; i < orders.length; i++) {
+            FillResults memory singleFillResults = fillOrder(
+                orders[i],
+                takerAssetFillAmounts[i],
+                signatures[i]
+            );
+            addFillResults(totalFillResults, singleFillResults);
+        }
+        return totalFillResults;
+    }
+
+    /// @dev Synchronously executes multiple calls of fillOrKill.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    ///         NOTE: makerAssetFilledAmount and takerAssetFilledAmount may include amounts filled of different assets.
+    function batchFillOrKillOrders(
+        LibOrder.Order[] memory orders,
+        uint256[] memory takerAssetFillAmounts,
+        bytes[] memory signatures
+    )
+        public
+        returns (FillResults memory totalFillResults)
+    {
+        for (uint256 i = 0; i < orders.length; i++) {
+            FillResults memory singleFillResults = fillOrKillOrder(
+                orders[i],
+                takerAssetFillAmounts[i],
+                signatures[i]
+            );
+            addFillResults(totalFillResults, singleFillResults);
+        }
+        return totalFillResults;
+    }
+
+    /// @dev Fills an order with specified parameters and ECDSA signature.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    ///         NOTE: makerAssetFilledAmount and takerAssetFilledAmount may include amounts filled of different assets.
+    function batchFillOrdersNoThrow(
+        LibOrder.Order[] memory orders,
+        uint256[] memory takerAssetFillAmounts,
+        bytes[] memory signatures
+    )
+        public
+        returns (FillResults memory totalFillResults)
+    {
+        for (uint256 i = 0; i < orders.length; i++) {
+            FillResults memory singleFillResults = fillOrderNoThrow(
+                orders[i],
+                takerAssetFillAmounts[i],
+                signatures[i]
+            );
+            addFillResults(totalFillResults, singleFillResults);
+        }
+        return totalFillResults;
+    }
+
+    /// @dev Synchronously executes multiple calls of fillOrder until total amount of takerAsset is sold by taker.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketSellOrders(
+        LibOrder.Order[] memory orders,
+        uint256 takerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        public
+        returns (FillResults memory totalFillResults)
+    {
+        bytes memory takerAssetData = orders[0].takerAssetData;
+    
+        for (uint256 i = 0; i < orders.length; i++) {
+
+            // We assume that asset being sold by taker is the same for each order.
+            // Rather than passing this in as calldata, we use the takerAssetData from the first order in all later orders.
+            orders[i].takerAssetData = takerAssetData;
+
+            // Calculate the remaining amount of takerAsset to sell
+            uint256 remainingTakerAssetFillAmount = safeSub(takerAssetFillAmount, totalFillResults.takerAssetFilledAmount);
+
+            // Attempt to sell the remaining amount of takerAsset
+            FillResults memory singleFillResults = fillOrder(
+                orders[i],
+                remainingTakerAssetFillAmount,
+                signatures[i]
+            );
+
+            // Update amounts filled and fees paid by maker and taker
+            addFillResults(totalFillResults, singleFillResults);
+
+            // Stop execution if the entire amount of takerAsset has been sold
+            if (totalFillResults.takerAssetFilledAmount == takerAssetFillAmount) {
+                break;
+            }
+        }
+        return totalFillResults;
+    }
+
+    /// @dev Synchronously executes multiple calls of fillOrder until total amount of takerAsset is sold by taker.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketSellOrdersNoThrow(
+        LibOrder.Order[] memory orders,
+        uint256 takerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        public
+        returns (FillResults memory totalFillResults)
+    {
+        bytes memory takerAssetData = orders[0].takerAssetData;
+
+        for (uint256 i = 0; i < orders.length; i++) {
+
+            // We assume that asset being sold by taker is the same for each order.
+            // Rather than passing this in as calldata, we use the takerAssetData from the first order in all later orders.
+            orders[i].takerAssetData = takerAssetData;
+
+            // Calculate the remaining amount of takerAsset to sell
+            uint256 remainingTakerAssetFillAmount = safeSub(takerAssetFillAmount, totalFillResults.takerAssetFilledAmount);
+
+            // Attempt to sell the remaining amount of takerAsset
+            FillResults memory singleFillResults = fillOrderNoThrow(
+                orders[i],
+                remainingTakerAssetFillAmount,
+                signatures[i]
+            );
+
+            // Update amounts filled and fees paid by maker and taker
+            addFillResults(totalFillResults, singleFillResults);
+
+            // Stop execution if the entire amount of takerAsset has been sold
+            if (totalFillResults.takerAssetFilledAmount == takerAssetFillAmount) {
+                break;
+            }
+        }
+        return totalFillResults;
+    }
+
+    /// @dev Synchronously executes multiple calls of fillOrder until total amount of makerAsset is bought by taker.
+    /// @param orders Array of order specifications.
+    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketBuyOrders(
+        LibOrder.Order[] memory orders,
+        uint256 makerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        public
+        returns (FillResults memory totalFillResults)
+    {
+        bytes memory makerAssetData = orders[0].makerAssetData;
+
+        for (uint256 i = 0; i < orders.length; i++) {
+
+            // We assume that asset being bought by taker is the same for each order.
+            // Rather than passing this in as calldata, we copy the makerAssetData from the first order onto all later orders.
+            orders[i].makerAssetData = makerAssetData;
+
+            // Calculate the remaining amount of makerAsset to buy
+            uint256 remainingMakerAssetFillAmount = safeSub(makerAssetFillAmount, totalFillResults.makerAssetFilledAmount);
+
+            // Convert the remaining amount of makerAsset to buy into remaining amount
+            // of takerAsset to sell, assuming entire amount can be sold in the current order
+            uint256 remainingTakerAssetFillAmount = getPartialAmount(
+                orders[i].takerAssetAmount,
+                orders[i].makerAssetAmount,
+                remainingMakerAssetFillAmount
+            );
+
+            // Attempt to sell the remaining amount of takerAsset
+            FillResults memory singleFillResults = fillOrder(
+                orders[i],
+                remainingTakerAssetFillAmount,
+                signatures[i]
+            );
+
+            // Update amounts filled and fees paid by maker and taker
+            addFillResults(totalFillResults, singleFillResults);
+
+            // Stop execution if the entire amount of makerAsset has been bought
+            if (totalFillResults.makerAssetFilledAmount == makerAssetFillAmount) {
+                break;
+            }
+        }
+        return totalFillResults;
+    }
+
+    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param orders Array of order specifications.
+    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketBuyOrdersNoThrow(
+        LibOrder.Order[] memory orders,
+        uint256 makerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        public
+        returns (FillResults memory totalFillResults)
+    {
+        bytes memory makerAssetData = orders[0].makerAssetData;
+
+        for (uint256 i = 0; i < orders.length; i++) {
+
+            // We assume that asset being bought by taker is the same for each order.
+            // Rather than passing this in as calldata, we copy the makerAssetData from the first order onto all later orders.
+            orders[i].makerAssetData = makerAssetData;
+
+            // Calculate the remaining amount of makerAsset to buy
+            uint256 remainingMakerAssetFillAmount = safeSub(makerAssetFillAmount, totalFillResults.makerAssetFilledAmount);
+
+            // Convert the remaining amount of makerAsset to buy into remaining amount
+            // of takerAsset to sell, assuming entire amount can be sold in the current order
+            uint256 remainingTakerAssetFillAmount = getPartialAmount(
+                orders[i].takerAssetAmount,
+                orders[i].makerAssetAmount,
+                remainingMakerAssetFillAmount
+            );
+
+            // Attempt to sell the remaining amount of takerAsset
+            FillResults memory singleFillResults = fillOrderNoThrow(
+                orders[i],
+                remainingTakerAssetFillAmount,
+                signatures[i]
+            );
+
+            // Update amounts filled and fees paid by maker and taker
+            addFillResults(totalFillResults, singleFillResults);
+
+            // Stop execution if the entire amount of makerAsset has been bought
+            if (totalFillResults.makerAssetFilledAmount == makerAssetFillAmount) {
+                break;
+            }
+        }
+        return totalFillResults;
+    }
+
+    /// @dev Synchronously cancels multiple orders in a single transaction.
+    /// @param orders Array of order specifications.
+    function batchCancelOrders(LibOrder.Order[] memory orders)
+        public
+    {
+        for (uint256 i = 0; i < orders.length; i++) {
+            cancelOrder(orders[i]);
+        }
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
new file mode 100644
index 000000000..66f3b5796
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
@@ -0,0 +1,36 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+contract IAssetProxyDispatcher {
+
+    /// @dev Registers an asset proxy to its asset proxy id.
+    ///      Once an asset proxy is registered, it cannot be unregistered.
+    /// @param assetProxy Address of new asset proxy to register.
+    function registerAssetProxy(address assetProxy)
+        external;
+
+    /// @dev Gets an asset proxy.
+    /// @param assetProxyId Id of the asset proxy.
+    /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered.
+    function getAssetProxy(bytes4 assetProxyId)
+        external
+        view
+        returns (address);
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchange.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchange.sol
new file mode 100644
index 000000000..9f21c18d7
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchange.sol
@@ -0,0 +1,36 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "./IExchangeCore.sol";
+import "./IMatchOrders.sol";
+import "./ISignatureValidator.sol";
+import "./ITransactions.sol";
+import "./IAssetProxyDispatcher.sol";
+import "./IWrapperFunctions.sol";
+
+contract IExchange is
+    IExchangeCore,
+    IMatchOrders,
+    ISignatureValidator,
+    ITransactions,
+    IAssetProxyDispatcher,
+    IWrapperFunctions
+{}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchangeCore.sol
new file mode 100644
index 000000000..98222f33f
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchangeCore.sol
@@ -0,0 +1,59 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../libs/LibOrder.sol";
+import "../libs/LibFillResults.sol";
+
+contract IExchangeCore {
+
+    /// @dev Cancels all orders created by makerAddress with a salt less than or equal to the targetOrderEpoch
+    ///      and senderAddress equal to msg.sender (or null address if msg.sender == makerAddress).
+    /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
+    function cancelOrdersUpTo(uint256 targetOrderEpoch)
+        external;
+
+    /// @dev Fills the input order.
+    /// @param order Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signature Proof that order has been created by maker.
+    /// @return Amounts filled and fees paid by maker and taker.
+    function fillOrder(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount,
+        bytes memory signature
+    )
+        public
+        returns (LibFillResults.FillResults memory fillResults);
+
+    /// @dev After calling, the order can not be filled anymore.
+    /// @param order Order struct containing order specifications.
+    function cancelOrder(LibOrder.Order memory order)
+        public;
+
+    /// @dev Gets information about an order: status, hash, and amount filled.
+    /// @param order Order to gather information on.
+    /// @return OrderInfo Information about the order and its state.
+    ///                   See LibOrder.OrderInfo for a complete description.
+    function getOrderInfo(LibOrder.Order memory order)
+        public
+        view
+        returns (LibOrder.OrderInfo memory orderInfo);
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IMatchOrders.sol
new file mode 100644
index 000000000..df009d063
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IMatchOrders.sol
@@ -0,0 +1,44 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../libs/LibOrder.sol";
+import "../libs/LibFillResults.sol";
+
+contract IMatchOrders {
+
+    /// @dev Match two complementary orders that have a profitable spread.
+    ///      Each order is filled at their respective price point. However, the calculations are
+    ///      carried out as though the orders are both being filled at the right order's price point.
+    ///      The profit made by the left order goes to the taker (who matched the two orders).
+    /// @param leftOrder First order to match.
+    /// @param rightOrder Second order to match.
+    /// @param leftSignature Proof that order was created by the left maker.
+    /// @param rightSignature Proof that order was created by the right maker.
+    /// @return matchedFillResults Amounts filled and fees paid by maker and taker of matched orders.
+    /// TODO: Make this function external once supported by Solidity (See Solidity Issues #3199, #1603)
+    function matchOrders(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder,
+        bytes memory leftSignature,
+        bytes memory rightSignature
+    )
+        public
+        returns (LibFillResults.MatchedFillResults memory matchedFillResults);
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ISignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ISignatureValidator.sol
new file mode 100644
index 000000000..511463309
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ISignatureValidator.sol
@@ -0,0 +1,56 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+contract ISignatureValidator {
+
+    /// @dev Approves a hash on-chain using any valid signature type.
+    ///      After presigning a hash, the preSign signature type will become valid for that hash and signer.
+    /// @param signerAddress Address that should have signed the given hash.
+    /// @param signature Proof that the hash has been signed by signer.
+    function preSign(
+        bytes32 hash,
+        address signerAddress,
+        bytes signature
+    )
+        external;
+    
+    /// @dev Approves/unnapproves a Validator contract to verify signatures on signer's behalf.
+    /// @param validatorAddress Address of Validator contract.
+    /// @param approval Approval or disapproval of  Validator contract.
+    function setSignatureValidatorApproval(
+        address validatorAddress,
+        bool approval
+    )
+        external;
+
+    /// @dev Verifies that a signature is valid.
+    /// @param hash Message hash that is signed.
+    /// @param signerAddress Address of signer.
+    /// @param signature Proof of signing.
+    /// @return Validity of order signature.
+    function isValidSignature(
+        bytes32 hash,
+        address signerAddress,
+        bytes memory signature
+    )
+        public
+        view
+        returns (bool isValid);
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ITransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ITransactions.sol
new file mode 100644
index 000000000..a7cab8f55
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ITransactions.sol
@@ -0,0 +1,34 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+pragma solidity ^0.4.24;
+
+contract ITransactions {
+
+    /// @dev Executes an exchange method call in the context of signer.
+    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
+    /// @param signerAddress Address of transaction signer.
+    /// @param data AbiV2 encoded calldata.
+    /// @param signature Proof of signer transaction by signer.
+    function executeTransaction(
+        uint256 salt,
+        address signerAddress,
+        bytes data,
+        bytes signature
+    )
+        external;
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IValidator.sol
new file mode 100644
index 000000000..0b1796a66
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IValidator.sol
@@ -0,0 +1,36 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.23;
+
+contract IValidator {
+
+    /// @dev Verifies that a signature is valid.
+    /// @param hash Message hash that is signed.
+    /// @param signerAddress Address that should have signed the given hash.
+    /// @param signature Proof of signing.
+    /// @return Validity of order signature.
+    function isValidSignature(
+        bytes32 hash,
+        address signerAddress,
+        bytes signature
+    )
+        external
+        view
+        returns (bool isValid);
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWallet.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWallet.sol
new file mode 100644
index 000000000..c86a2c057
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWallet.sol
@@ -0,0 +1,34 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+contract IWallet {
+
+    /// @dev Verifies that a signature is valid.
+    /// @param hash Message hash that is signed.
+    /// @param signature Proof of signing.
+    /// @return Validity of order signature.
+    function isValidSignature(
+        bytes32 hash,
+        bytes signature
+    )
+        external
+        view
+        returns (bool isValid);
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWrapperFunctions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWrapperFunctions.sol
new file mode 100644
index 000000000..84bb683bc
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWrapperFunctions.sol
@@ -0,0 +1,150 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../libs/LibOrder.sol";
+import "../libs/LibFillResults.sol";
+
+contract IWrapperFunctions {
+    /// @dev Fills the input order. Reverts if exact takerAssetFillAmount not filled.
+    /// @param order LibOrder.Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signature Proof that order has been created by maker.
+    function fillOrKillOrder(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount,
+        bytes memory signature
+    )
+        public
+        returns (LibFillResults.FillResults memory fillResults);
+
+    /// @dev Fills an order with specified parameters and ECDSA signature.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param order LibOrder.Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signature Proof that order has been created by maker.
+    /// @return Amounts filled and fees paid by maker and taker.
+    function fillOrderNoThrow(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount,
+        bytes memory signature
+    )
+        public
+        returns (LibFillResults.FillResults memory fillResults);
+
+    /// @dev Synchronously executes multiple calls of fillOrder.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function batchFillOrders(
+        LibOrder.Order[] memory orders,
+        uint256[] memory takerAssetFillAmounts,
+        bytes[] memory signatures
+    )
+        public
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Synchronously executes multiple calls of fillOrKill.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function batchFillOrKillOrders(
+        LibOrder.Order[] memory orders,
+        uint256[] memory takerAssetFillAmounts,
+        bytes[] memory signatures
+    )
+        public
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Fills an order with specified parameters and ECDSA signature.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmounts Array of desired amounts of takerAsset to sell in orders.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function batchFillOrdersNoThrow(
+        LibOrder.Order[] memory orders,
+        uint256[] memory takerAssetFillAmounts,
+        bytes[] memory signatures
+    )
+        public
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Synchronously executes multiple calls of fillOrder until total amount of takerAsset is sold by taker.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signatures Proofs that orders have been created by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketSellOrders(
+        LibOrder.Order[] memory orders,
+        uint256 takerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        public
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Synchronously executes multiple calls of fillOrder until total amount of takerAsset is sold by taker.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param orders Array of order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketSellOrdersNoThrow(
+        LibOrder.Order[] memory orders,
+        uint256 takerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        public
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Synchronously executes multiple calls of fillOrder until total amount of makerAsset is bought by taker.
+    /// @param orders Array of order specifications.
+    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketBuyOrders(
+        LibOrder.Order[] memory orders,
+        uint256 makerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        public
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
+    ///      Returns false if the transaction would otherwise revert.
+    /// @param orders Array of order specifications.
+    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
+    /// @param signatures Proofs that orders have been signed by makers.
+    /// @return Amounts filled and fees paid by makers and taker.
+    function marketBuyOrdersNoThrow(
+        LibOrder.Order[] memory orders,
+        uint256 makerAssetFillAmount,
+        bytes[] memory signatures
+    )
+        public
+        returns (LibFillResults.FillResults memory totalFillResults);
+
+    /// @dev Synchronously cancels multiple orders in a single transaction.
+    /// @param orders Array of order specifications.
+    function batchCancelOrders(LibOrder.Order[] memory orders)
+        public;
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibConstants.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibConstants.sol
new file mode 100644
index 000000000..488ca956c
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibConstants.sol
@@ -0,0 +1,34 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+contract LibConstants {
+   
+    // Asset data for ZRX token. Used for fee transfers.
+    // @TODO: Hardcode constant when we deploy. Currently 
+    //        not constant to make testing easier.
+    bytes public ZRX_ASSET_DATA;
+
+    // @TODO: Remove when we deploy.
+    constructor (bytes memory zrxAssetData)
+        public
+    {
+        ZRX_ASSET_DATA = zrxAssetData;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibEIP712.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibEIP712.sol
new file mode 100644
index 000000000..b983347a4
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibEIP712.sol
@@ -0,0 +1,64 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+contract LibEIP712 {
+    // EIP191 header for EIP712 prefix
+    string constant EIP191_HEADER = "\x19\x01";
+
+    // EIP712 Domain Name value
+    string constant EIP712_DOMAIN_NAME = "0x Protocol";
+
+    // EIP712 Domain Version value
+    string constant EIP712_DOMAIN_VERSION = "2";
+
+    // Hash of the EIP712 Domain Separator Schema
+    bytes32 public constant EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH = keccak256(abi.encodePacked(
+        "EIP712Domain(",
+        "string name,",
+        "string version,",
+        "address verifyingContract",
+        ")"
+    ));
+
+    // Hash of the EIP712 Domain Separator data
+    bytes32 public EIP712_DOMAIN_HASH;
+
+    constructor ()
+        public
+    {
+        EIP712_DOMAIN_HASH = keccak256(abi.encode(
+            EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH,
+            keccak256(bytes(EIP712_DOMAIN_NAME)),
+            keccak256(bytes(EIP712_DOMAIN_VERSION)),
+            address(this)
+        ));
+    }
+
+    /// @dev Calculates EIP712 encoding for a hash struct in this EIP712 Domain.
+    /// @param hashStruct The EIP712 hash struct.
+    /// @return EIP712 hash applied to this EIP712 Domain.
+    function hashEIP712Message(bytes32 hashStruct)
+        internal
+        view
+        returns (bytes32)
+    {
+        return keccak256(abi.encodePacked(EIP191_HEADER, EIP712_DOMAIN_HASH, hashStruct));
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibExchangeErrors.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibExchangeErrors.sol
new file mode 100644
index 000000000..01aa78a1d
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibExchangeErrors.sol
@@ -0,0 +1,68 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+/// @dev This contract documents the revert reasons used in the Exchange contract.
+/// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
+contract LibExchangeErrors {
+
+    /// Order validation errors ///
+    string constant ORDER_UNFILLABLE = "ORDER_UNFILLABLE";                              // Order cannot be filled.
+    string constant INVALID_MAKER = "INVALID_MAKER";                                    // Invalid makerAddress.
+    string constant INVALID_TAKER = "INVALID_TAKER";                                    // Invalid takerAddress.
+    string constant INVALID_SENDER = "INVALID_SENDER";                                  // Invalid `msg.sender`.
+    string constant INVALID_ORDER_SIGNATURE = "INVALID_ORDER_SIGNATURE";                // Signature validation failed. 
+    
+    /// fillOrder validation errors ///
+    string constant INVALID_TAKER_AMOUNT = "INVALID_TAKER_AMOUNT";                      // takerAssetFillAmount cannot equal 0.
+    string constant ROUNDING_ERROR = "ROUNDING_ERROR";                                  // Rounding error greater than 0.1% of takerAssetFillAmount. 
+    
+    /// Signature validation errors ///
+    string constant INVALID_SIGNATURE = "INVALID_SIGNATURE";                            // Signature validation failed. 
+    string constant SIGNATURE_ILLEGAL = "SIGNATURE_ILLEGAL";                            // Signature type is illegal.
+    string constant SIGNATURE_UNSUPPORTED = "SIGNATURE_UNSUPPORTED";                    // Signature type unsupported.
+    
+    /// cancelOrdersUptTo errors ///
+    string constant INVALID_NEW_ORDER_EPOCH = "INVALID_NEW_ORDER_EPOCH";                // Specified salt must be greater than or equal to existing orderEpoch.
+
+    /// fillOrKillOrder errors ///
+    string constant COMPLETE_FILL_FAILED = "COMPLETE_FILL_FAILED";                      // Desired takerAssetFillAmount could not be completely filled. 
+
+    /// matchOrders errors ///
+    string constant NEGATIVE_SPREAD_REQUIRED = "NEGATIVE_SPREAD_REQUIRED";              // Matched orders must have a negative spread.
+
+    /// Transaction errors ///
+    string constant REENTRANCY_ILLEGAL = "REENTRANCY_ILLEGAL";                          // Recursive reentrancy is not allowed. 
+    string constant INVALID_TX_HASH = "INVALID_TX_HASH";                                // Transaction has already been executed. 
+    string constant INVALID_TX_SIGNATURE = "INVALID_TX_SIGNATURE";                      // Signature validation failed. 
+    string constant FAILED_EXECUTION = "FAILED_EXECUTION";                              // Transaction execution failed. 
+    
+    /// registerAssetProxy errors ///
+    string constant ASSET_PROXY_ALREADY_EXISTS = "ASSET_PROXY_ALREADY_EXISTS";          // AssetProxy with same id already exists.
+
+    /// dispatchTransferFrom errors ///
+    string constant ASSET_PROXY_DOES_NOT_EXIST = "ASSET_PROXY_DOES_NOT_EXIST";          // No assetProxy registered at given id.
+    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                                // Asset transfer unsuccesful.
+
+    /// Length validation errors ///
+    string constant LENGTH_GREATER_THAN_0_REQUIRED = "LENGTH_GREATER_THAN_0_REQUIRED";  // Byte array must have a length greater than 0.
+    string constant LENGTH_GREATER_THAN_3_REQUIRED = "LENGTH_GREATER_THAN_3_REQUIRED";  // Byte array must have a length greater than 3.
+    string constant LENGTH_0_REQUIRED = "LENGTH_0_REQUIRED";                            // Byte array must have a length of 0.
+    string constant LENGTH_65_REQUIRED = "LENGTH_65_REQUIRED";                          // Byte array must have a length of 65.
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibFillResults.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibFillResults.sol
new file mode 100644
index 000000000..63f1b8c87
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibFillResults.sol
@@ -0,0 +1,53 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../../utils/SafeMath/SafeMath.sol";
+
+contract LibFillResults is
+    SafeMath
+{
+
+    struct FillResults {
+        uint256 makerAssetFilledAmount;  // Total amount of makerAsset(s) filled.
+        uint256 takerAssetFilledAmount;  // Total amount of takerAsset(s) filled.
+        uint256 makerFeePaid;            // Total amount of ZRX paid by maker(s) to feeRecipient(s).
+        uint256 takerFeePaid;            // Total amount of ZRX paid by taker to feeRecipients(s).
+    }
+
+    struct MatchedFillResults {
+        FillResults left;                    // Amounts filled and fees paid of left order.
+        FillResults right;                   // Amounts filled and fees paid of right order.
+        uint256 leftMakerAssetSpreadAmount;  // Spread between price of left and right order, denominated in the left order's makerAsset, paid to taker.
+    }
+
+    /// @dev Adds properties of both FillResults instances.
+    ///      Modifies the first FillResults instance specified.
+    /// @param totalFillResults Fill results instance that will be added onto.
+    /// @param singleFillResults Fill results instance that will be added to totalFillResults.
+    function addFillResults(FillResults memory totalFillResults, FillResults memory singleFillResults)
+        internal
+        pure
+    {
+        totalFillResults.makerAssetFilledAmount = safeAdd(totalFillResults.makerAssetFilledAmount, singleFillResults.makerAssetFilledAmount);
+        totalFillResults.takerAssetFilledAmount = safeAdd(totalFillResults.takerAssetFilledAmount, singleFillResults.takerAssetFilledAmount);
+        totalFillResults.makerFeePaid = safeAdd(totalFillResults.makerFeePaid, singleFillResults.makerFeePaid);
+        totalFillResults.takerFeePaid = safeAdd(totalFillResults.takerFeePaid, singleFillResults.takerFeePaid);
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
new file mode 100644
index 000000000..bfe2fd33f
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
@@ -0,0 +1,72 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../../utils/SafeMath/SafeMath.sol";
+
+contract LibMath is
+    SafeMath
+{
+
+    /// @dev Calculates partial value given a numerator and denominator.
+    /// @param numerator Numerator.
+    /// @param denominator Denominator.
+    /// @param target Value to calculate partial of.
+    /// @return Partial value of target.
+    function getPartialAmount(
+        uint256 numerator,
+        uint256 denominator,
+        uint256 target)
+        internal
+        pure
+        returns (uint256 partialAmount)
+    {
+        partialAmount = safeDiv(
+            safeMul(numerator, target),
+            denominator
+        );
+        return partialAmount;
+    }
+
+    /// @dev Checks if rounding error > 0.1%.
+    /// @param numerator Numerator.
+    /// @param denominator Denominator.
+    /// @param target Value to multiply with numerator/denominator.
+    /// @return Rounding error is present.
+    function isRoundingError(
+        uint256 numerator,
+        uint256 denominator,
+        uint256 target)
+        internal
+        pure
+        returns (bool isError)
+    {
+        uint256 remainder = mulmod(target, numerator, denominator);
+        if (remainder == 0) {
+            return false; // No rounding error.
+        }
+
+        uint256 errPercentageTimes1000000 = safeDiv(
+            safeMul(remainder, 1000000),
+            safeMul(numerator, target)
+        );
+        isError = errPercentageTimes1000000 > 1000;
+        return isError;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibOrder.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibOrder.sol
new file mode 100644
index 000000000..954f94f76
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibOrder.sol
@@ -0,0 +1,135 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "./LibEIP712.sol";
+
+contract LibOrder is
+    LibEIP712
+{
+
+    // Hash for the EIP712 Order Schema
+    bytes32 constant EIP712_ORDER_SCHEMA_HASH = keccak256(abi.encodePacked(
+        "Order(",
+        "address makerAddress,",
+        "address takerAddress,",
+        "address feeRecipientAddress,",
+        "address senderAddress,",
+        "uint256 makerAssetAmount,",
+        "uint256 takerAssetAmount,",
+        "uint256 makerFee,",
+        "uint256 takerFee,",
+        "uint256 expirationTimeSeconds,",
+        "uint256 salt,",
+        "bytes makerAssetData,",
+        "bytes takerAssetData",
+        ")"
+    ));
+
+    // A valid order remains fillable until it is expired, fully filled, or cancelled.
+    // An order's state is unaffected by external factors, like account balances.
+    enum OrderStatus {
+        INVALID,                     // Default value
+        INVALID_MAKER_ASSET_AMOUNT,  // Order does not have a valid maker asset amount
+        INVALID_TAKER_ASSET_AMOUNT,  // Order does not have a valid taker asset amount
+        FILLABLE,                    // Order is fillable
+        EXPIRED,                     // Order has already expired
+        FULLY_FILLED,                // Order is fully filled
+        CANCELLED                    // Order has been cancelled
+    }
+
+    struct Order {
+        address makerAddress;           // Address that created the order.      
+        address takerAddress;           // Address that is allowed to fill the order. If set to 0, any address is allowed to fill the order.          
+        address feeRecipientAddress;    // Address that will recieve fees when order is filled.      
+        address senderAddress;          // Address that is allowed to call Exchange contract methods that affect this order. If set to 0, any address is allowed to call these methods.
+        uint256 makerAssetAmount;       // Amount of makerAsset being offered by maker. Must be greater than 0.        
+        uint256 takerAssetAmount;       // Amount of takerAsset being bid on by maker. Must be greater than 0.        
+        uint256 makerFee;               // Amount of ZRX paid to feeRecipient by maker when order is filled. If set to 0, no transfer of ZRX from maker to feeRecipient will be attempted.
+        uint256 takerFee;               // Amount of ZRX paid to feeRecipient by taker when order is filled. If set to 0, no transfer of ZRX from taker to feeRecipient will be attempted.
+        uint256 expirationTimeSeconds;  // Timestamp in seconds at which order expires.          
+        uint256 salt;                   // Arbitrary number to facilitate uniqueness of the order's hash.     
+        bytes makerAssetData;           // Encoded data that can be decoded by a specified proxy contract when transferring makerAsset. The last byte references the id of this proxy.
+        bytes takerAssetData;           // Encoded data that can be decoded by a specified proxy contract when transferring takerAsset. The last byte references the id of this proxy.
+    }
+
+    struct OrderInfo {
+        uint8 orderStatus;                    // Status that describes order's validity and fillability.
+        bytes32 orderHash;                    // EIP712 hash of the order (see LibOrder.getOrderHash).
+        uint256 orderTakerAssetFilledAmount;  // Amount of order that has already been filled.
+    }
+
+    /// @dev Calculates Keccak-256 hash of the order.
+    /// @param order The order structure.
+    /// @return Keccak-256 EIP712 hash of the order.
+    function getOrderHash(Order memory order)
+        internal
+        view
+        returns (bytes32 orderHash)
+    {
+        orderHash = hashEIP712Message(hashOrder(order));
+        return orderHash;
+    }
+
+    /// @dev Calculates EIP712 hash of the order.
+    /// @param order The order structure.
+    /// @return EIP712 hash of the order.
+    function hashOrder(Order memory order)
+        internal
+        pure
+        returns (bytes32 result)
+    {
+        bytes32 schemaHash = EIP712_ORDER_SCHEMA_HASH;
+        bytes32 makerAssetDataHash = keccak256(order.makerAssetData);
+        bytes32 takerAssetDataHash = keccak256(order.takerAssetData);
+        // Assembly for more efficiently computing:
+        //   keccak256(abi.encode(
+        //       order.makerAddress,
+        //       order.takerAddress,
+        //       order.feeRecipientAddress,
+        //       order.senderAddress,
+        //       order.makerAssetAmount,
+        //       order.takerAssetAmount,
+        //       order.makerFee,
+        //       order.takerFee,
+        //       order.expirationTimeSeconds,
+        //       order.salt,
+        //       keccak256(order.makerAssetData),
+        //       keccak256(order.takerAssetData)
+        //   ));
+        assembly {
+            // Backup
+            let temp1 := mload(sub(order,  32))
+            let temp2 := mload(add(order, 320))
+            let temp3 := mload(add(order, 352))
+            
+            // Hash in place
+            mstore(sub(order,  32), schemaHash)
+            mstore(add(order, 320), makerAssetDataHash)
+            mstore(add(order, 352), takerAssetDataHash)
+            result := keccak256(sub(order, 32), 416)
+            
+            // Restore
+            mstore(sub(order,  32), temp1)
+            mstore(add(order, 320), temp2)
+            mstore(add(order, 352), temp3)
+        }
+        return result;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
new file mode 100644
index 000000000..5bf59c6ce
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
@@ -0,0 +1,46 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../interfaces/IAssetProxyDispatcher.sol";
+
+contract MAssetProxyDispatcher is
+    IAssetProxyDispatcher
+{
+
+    // Logs registration of new asset proxy
+    event AssetProxyRegistered(
+        bytes4 id,              // Id of new registered AssetProxy.
+        address assetProxy      // Address of new registered AssetProxy.
+    );
+
+    /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws.
+    /// @param assetData Byte array encoded for the asset.
+    /// @param from Address to transfer token from.
+    /// @param to Address to transfer token to.
+    /// @param amount Amount of token to transfer.
+    function dispatchTransferFrom(
+        bytes memory assetData,
+        address from,
+        address to,
+        uint256 amount
+    )
+        internal;
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
new file mode 100644
index 000000000..6e406e1c4
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
@@ -0,0 +1,127 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../libs/LibOrder.sol";
+import "../libs/LibFillResults.sol";
+import "../interfaces/IExchangeCore.sol";
+
+contract MExchangeCore is
+    IExchangeCore
+{
+    // Fill event is emitted whenever an order is filled.
+    event Fill(
+        address indexed makerAddress,         // Address that created the order.      
+        address indexed feeRecipientAddress,  // Address that received fees.
+        address takerAddress,                 // Address that filled the order.
+        address senderAddress,                // Address that called the Exchange contract (msg.sender).
+        uint256 makerAssetFilledAmount,       // Amount of makerAsset sold by maker and bought by taker. 
+        uint256 takerAssetFilledAmount,       // Amount of takerAsset sold by taker and bought by maker.
+        uint256 makerFeePaid,                 // Amount of ZRX paid to feeRecipient by maker.
+        uint256 takerFeePaid,                 // Amount of ZRX paid to feeRecipient by taker.
+        bytes32 indexed orderHash,            // EIP712 hash of order (see LibOrder.getOrderHash).
+        bytes makerAssetData,                 // Encoded data specific to makerAsset. 
+        bytes takerAssetData                  // Encoded data specific to takerAsset.
+    );
+
+    // Cancel event is emitted whenever an individual order is cancelled.
+    event Cancel(
+        address indexed makerAddress,         // Address that created the order.      
+        address indexed feeRecipientAddress,  // Address that would have recieved fees if order was filled.   
+        address senderAddress,                // Address that called the Exchange contract (msg.sender).
+        bytes32 indexed orderHash,            // EIP712 hash of order (see LibOrder.getOrderHash).
+        bytes makerAssetData,                 // Encoded data specific to makerAsset. 
+        bytes takerAssetData                  // Encoded data specific to takerAsset.
+    );
+
+    // CancelUpTo event is emitted whenever `cancelOrdersUpTo` is executed succesfully.
+    event CancelUpTo(
+        address indexed makerAddress,         // Orders cancelled must have been created by this address.
+        address indexed senderAddress,        // Orders cancelled must have a `senderAddress` equal to this address.
+        uint256 orderEpoch                    // Orders specified makerAddress and senderAddress with a salt <= this value are considered cancelled.
+    );
+
+    /// @dev Updates state with results of a fill order.
+    /// @param order that was filled.
+    /// @param takerAddress Address of taker who filled the order.
+    /// @param orderTakerAssetFilledAmount Amount of order already filled.
+    /// @return fillResults Amounts filled and fees paid by maker and taker.
+    function updateFilledState(
+        LibOrder.Order memory order,
+        address takerAddress,
+        bytes32 orderHash,
+        uint256 orderTakerAssetFilledAmount,
+        LibFillResults.FillResults memory fillResults
+    )
+        internal;
+
+    /// @dev Updates state with results of cancelling an order.
+    ///      State is only updated if the order is currently fillable.
+    ///      Otherwise, updating state would have no effect.
+    /// @param order that was cancelled.
+    /// @param orderHash Hash of order that was cancelled.
+    function updateCancelledState(
+        LibOrder.Order memory order,
+        bytes32 orderHash
+    )
+        internal;
+
+    /// @dev Validates context for fillOrder. Succeeds or throws.
+    /// @param order to be filled.
+    /// @param orderInfo Status, orderHash, and amount already filled of order.
+    /// @param takerAddress Address of order taker.
+    /// @param takerAssetFillAmount Desired amount of order to fill by taker.
+    /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
+    /// @param signature Proof that the orders was created by its maker.
+    function assertValidFill(
+        LibOrder.Order memory order,
+        LibOrder.OrderInfo memory orderInfo,
+        address takerAddress,
+        uint256 takerAssetFillAmount,
+        uint256 takerAssetFilledAmount,
+        bytes memory signature
+    )
+        internal
+        view;
+
+
+    /// @dev Validates context for cancelOrder. Succeeds or throws.
+    /// @param order to be cancelled.
+    /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
+    function assertValidCancel(
+        LibOrder.Order memory order,
+        LibOrder.OrderInfo memory orderInfo
+    )
+        internal
+        view;
+
+    /// @dev Calculates amounts filled and fees paid by maker and taker.
+    /// @param order to be filled.
+    /// @param takerAssetFilledAmount Amount of takerAsset that will be filled.
+    /// @return fillResults Amounts filled and fees paid by maker and taker.
+    function calculateFillResults(
+        LibOrder.Order memory order,
+        uint256 takerAssetFilledAmount
+    )
+        internal
+        pure
+        returns (LibFillResults.FillResults memory fillResults);
+
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MMatchOrders.sol
new file mode 100644
index 000000000..abe7c3596
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MMatchOrders.sol
@@ -0,0 +1,58 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../libs/LibOrder.sol";
+import "../libs/LibFillResults.sol";
+import "../interfaces/IMatchOrders.sol";
+
+contract MMatchOrders is
+    IMatchOrders
+{
+
+    /// @dev Validates context for matchOrders. Succeeds or throws.
+    /// @param leftOrder First order to match.
+    /// @param rightOrder Second order to match.
+    function assertValidMatch(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder
+    )
+        internal
+        pure;
+
+    /// @dev Calculates fill amounts for the matched orders.
+    ///      Each order is filled at their respective price point. However, the calculations are
+    ///      carried out as though the orders are both being filled at the right order's price point.
+    ///      The profit made by the leftOrder order goes to the taker (who matched the two orders).
+    /// @param leftOrder First order to match.
+    /// @param rightOrder Second order to match.
+    /// @param leftOrderTakerAssetFilledAmount Amount of left order already filled.
+    /// @param rightOrderTakerAssetFilledAmount Amount of right order already filled.
+    /// @param matchedFillResults Amounts to fill and fees to pay by maker and taker of matched orders.
+    function calculateMatchedFillResults(
+        LibOrder.Order memory leftOrder,
+        LibOrder.Order memory rightOrder,
+        uint256 leftOrderTakerAssetFilledAmount,
+        uint256 rightOrderTakerAssetFilledAmount
+    )
+        internal
+        pure
+        returns (LibFillResults.MatchedFillResults memory matchedFillResults);
+
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
new file mode 100644
index 000000000..6cc1d7a10
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
@@ -0,0 +1,45 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../interfaces/ISignatureValidator.sol";
+
+contract MSignatureValidator is
+    ISignatureValidator
+{
+    event SignatureValidatorApproval(
+        address indexed signerAddress,     // Address that approves or disapproves a contract to verify signatures.
+        address indexed validatorAddress,  // Address of signature validator contract.
+        bool approved                      // Approval or disapproval of validator contract.
+    );
+
+    // Allowed signature types.
+    enum SignatureType {
+        Illegal,         // 0x00, default value
+        Invalid,         // 0x01
+        EIP712,          // 0x02
+        EthSign,         // 0x03
+        Caller,          // 0x04
+        Wallet,          // 0x05
+        Validator,       // 0x06
+        PreSigned,       // 0x07
+        Trezor,          // 0x08
+        NSignatureTypes  // 0x09, number of signature types. Always leave at end.
+    }
+}
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MTransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MTransactions.sol
new file mode 100644
index 000000000..e2f89de01
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MTransactions.sol
@@ -0,0 +1,35 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+pragma solidity ^0.4.24;
+
+import "../interfaces/ITransactions.sol";
+
+contract MTransactions is
+    ITransactions
+{
+
+    /// @dev The current function will be called in the context of this address (either 0x transaction signer or `msg.sender`).
+    ///      If calling a fill function, this address will represent the taker.
+    ///      If calling a cancel function, this address will represent the maker.
+    /// @return Signer of 0x transaction if entry point is `executeTransaction`.
+    ///         `msg.sender` if entry point is any other function.
+    function getCurrentContextAddress()
+        internal
+        view
+        returns (address);
+}
diff --git a/packages/contracts/src/2.0.0/test/DummyERC20Token/DummyERC20Token.sol b/packages/contracts/src/2.0.0/test/DummyERC20Token/DummyERC20Token.sol
new file mode 100644
index 000000000..b2fe2df06
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/DummyERC20Token/DummyERC20Token.sol
@@ -0,0 +1,57 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../Mintable/Mintable.sol";
+import "../../utils/Ownable/Ownable.sol";
+
+contract DummyERC20Token is Mintable, Ownable {
+    string public name;
+    string public symbol;
+    uint256 public decimals;
+
+    constructor (
+        string _name,
+        string _symbol,
+        uint256 _decimals,
+        uint256 _totalSupply
+    )
+        public
+    {
+        name = _name;
+        symbol = _symbol;
+        decimals = _decimals;
+        totalSupply = _totalSupply;
+        balances[msg.sender] = _totalSupply;
+    }
+
+    function setBalance(address _target, uint256 _value)
+        public
+        onlyOwner
+    {
+        uint256 currBalance = balanceOf(_target);
+        if (_value < currBalance) {
+            totalSupply = safeSub(totalSupply, safeSub(currBalance, _value));
+        } else {
+            totalSupply = safeAdd(totalSupply, safeSub(_value, currBalance));
+        }
+        balances[_target] = _value;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/DummyERC721Receiver/DummyERC721Receiver.sol b/packages/contracts/src/2.0.0/test/DummyERC721Receiver/DummyERC721Receiver.sol
new file mode 100644
index 000000000..c584d0b54
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/DummyERC721Receiver/DummyERC721Receiver.sol
@@ -0,0 +1,63 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2016 Smart Contract Solutions, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../tokens/ERC721Token/IERC721Receiver.sol";
+
+contract DummyERC721Receiver is
+    IERC721Receiver
+{
+
+    event TokenReceived(
+        address from,
+        uint256 tokenId,
+        bytes data
+    );
+
+    /**
+    * @notice Handle the receipt of an NFT
+    * @dev The ERC721 smart contract calls this function on the recipient
+    *  after a `safetransfer`. This function MAY throw to revert and reject the
+    *  transfer. This function MUST use 50,000 gas or less. Return of other
+    *  than the magic value MUST result in the transaction being reverted.
+    *  Note: the contract address is always the message sender.
+    * @param _from The sending address
+    * @param _tokenId The NFT identifier which is being transfered
+    * @param _data Additional data with no specified format
+    * @return `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
+    */
+    function onERC721Received(
+        address _from,
+        uint256 _tokenId,
+        bytes _data
+    )
+        public
+        returns (bytes4)
+    {
+        emit TokenReceived(_from, _tokenId, _data);
+        return ERC721_RECEIVED;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol b/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol
new file mode 100644
index 000000000..78ea96447
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol
@@ -0,0 +1,75 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../tokens/ERC721Token/ERC721Token.sol";
+import "../../utils/Ownable/Ownable.sol";
+
+contract DummyERC721Token is
+    Ownable,
+    ERC721Token
+{
+
+    /**
+    * @dev Constructor passes its arguments to the base ERC721Token constructor
+    * @param name of token
+    * @param symbol of token
+    */
+    constructor (
+        string name,
+        string symbol
+    )
+        public
+        ERC721Token(name, symbol)
+    {}
+
+    /**
+    * @dev Function to mint a new token
+    * @dev Reverts if the given token ID already exists
+    * @param to address the beneficiary that will own the minted token
+    * @param tokenId uint256 ID of the token to be minted by the msg.sender
+    */
+    function mint(address to, uint256 tokenId)
+        public
+        onlyOwner
+    {
+        require(
+            !exists(tokenId),
+            "Token with tokenId already exists."
+        );
+        _mint(to, tokenId);
+    }
+
+    /**
+    * @dev Function to burn a token
+    * @dev Reverts if the given token ID doesn't exist
+    * @param tokenId uint256 ID of the token to be minted by the msg.sender
+    */
+    function burn(address owner, uint256 tokenId)
+        public
+        onlyOwner
+    {
+        require(
+            exists(tokenId),
+            "Token with tokenId does not exist."
+        );
+        _burn(owner, tokenId);
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/ExchangeWrapper/ExchangeWrapper.sol b/packages/contracts/src/2.0.0/test/ExchangeWrapper/ExchangeWrapper.sol
new file mode 100644
index 000000000..5baaf6e5a
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/ExchangeWrapper/ExchangeWrapper.sol
@@ -0,0 +1,98 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/interfaces/IExchange.sol";
+import "../../protocol/Exchange/libs/LibOrder.sol";
+
+contract ExchangeWrapper {
+
+    // Exchange contract.
+    IExchange EXCHANGE;
+
+    constructor (address _exchange)
+        public
+    {
+        EXCHANGE = IExchange(_exchange);
+    }
+
+    /// @dev Fills an order using `msg.sender` as the taker.
+    /// @param order Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
+    /// @param orderSignature Proof that order has been created by maker.
+    /// @param takerSignature Proof that taker wishes to call this function with given params.
+    function fillOrder(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount,
+        uint256 salt,
+        bytes memory orderSignature,
+        bytes memory takerSignature
+    )
+        public
+    {
+        address takerAddress = msg.sender;
+
+        // Encode arguments into byte array.
+        bytes memory data = abi.encodeWithSelector(
+            EXCHANGE.fillOrder.selector,
+            order,
+            takerAssetFillAmount,
+            orderSignature
+        );
+
+        // Call `fillOrder` via `executeTransaction`.
+        EXCHANGE.executeTransaction(
+            salt,
+            takerAddress,
+            data,
+            takerSignature
+        );
+    }
+
+    /// @dev Cancels all orders created by sender with a salt less than or equal to the targetOrderEpoch
+    ///      and senderAddress equal to this contract.
+    /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
+    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
+    /// @param makerSignature Proof that maker wishes to call this function with given params.
+    function cancelOrdersUpTo(
+        uint256 targetOrderEpoch,
+        uint256 salt,
+        bytes makerSignature
+    )
+        external
+    {
+        address makerAddress = msg.sender;
+
+        // Encode arguments into byte array.
+        bytes memory data = abi.encodeWithSelector(
+            EXCHANGE.cancelOrdersUpTo.selector,
+            targetOrderEpoch
+        );
+
+        // Call `cancelOrdersUpTo` via `executeTransaction`.
+        EXCHANGE.executeTransaction(
+            salt,
+            makerAddress,
+            data,
+            makerSignature
+        );
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/Mintable/Mintable.sol b/packages/contracts/src/2.0.0/test/Mintable/Mintable.sol
new file mode 100644
index 000000000..a91bfee9e
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/Mintable/Mintable.sol
@@ -0,0 +1,40 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol";
+import "../../utils/SafeMath/SafeMath.sol";
+
+/*
+ * Mintable
+ * Base contract that creates a mintable UnlimitedAllowanceToken
+ */
+contract Mintable is UnlimitedAllowanceToken, SafeMath {
+    function mint(uint256 _value)
+        public
+    {
+        require(
+            _value <= 100000000000000000000,
+            "Minting more than 100000000000000000000 is not allowed."
+        );
+        balances[msg.sender] = safeAdd(_value, balances[msg.sender]);
+        totalSupply = safeAdd(totalSupply, _value);
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
new file mode 100644
index 000000000..2ae69e0ef
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
@@ -0,0 +1,34 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/MixinAssetProxyDispatcher.sol";
+
+contract TestAssetProxyDispatcher is MixinAssetProxyDispatcher {
+    function publicDispatchTransferFrom(
+        bytes memory assetData,
+        address from,
+        address to,
+        uint256 amount)
+        public
+    {
+        dispatchTransferFrom(assetData, from, to, amount);
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/TestAssetProxyOwner/TestAssetProxyOwner.sol b/packages/contracts/src/2.0.0/test/TestAssetProxyOwner/TestAssetProxyOwner.sol
new file mode 100644
index 000000000..2abcd17a0
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/TestAssetProxyOwner/TestAssetProxyOwner.sol
@@ -0,0 +1,56 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../protocol/AssetProxyOwner/AssetProxyOwner.sol";
+
+contract TestAssetProxyOwner is
+    AssetProxyOwner
+{
+    constructor(
+        address[] memory _owners,
+        address[] memory _assetProxyContracts,
+        uint256 _required,
+        uint256 _secondsTimeLocked
+    )
+        public
+        AssetProxyOwner(_owners, _assetProxyContracts, _required, _secondsTimeLocked)
+    {
+    }
+    
+    function testValidRemoveAuthorizedAddressAtIndexTx(uint256 id)
+        public
+        validRemoveAuthorizedAddressAtIndexTx(id)
+        returns (bool)
+    {
+        // Do nothing. We expect reverts through the modifier
+        return true;
+    }
+    
+    /// @dev Compares first 4 bytes of byte array to `removeAuthorizedAddressAtIndex` function selector.
+    /// @param data Transaction data.
+    /// @return Successful if data is a call to `removeAuthorizedAddressAtIndex`.
+    function isFunctionRemoveAuthorizedAddressAtIndex(bytes memory data)
+        public
+        pure
+        returns (bool)
+    {
+        return data.readBytes4(0) == REMOVE_AUTHORIZED_ADDRESS_AT_INDEX_SELECTOR;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/TestLibBytes/TestLibBytes.sol b/packages/contracts/src/2.0.0/test/TestLibBytes/TestLibBytes.sol
new file mode 100644
index 000000000..f45faaf36
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/TestLibBytes/TestLibBytes.sol
@@ -0,0 +1,269 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../utils/LibBytes/LibBytes.sol";
+
+contract TestLibBytes {
+    
+    using LibBytes for bytes;
+
+    /// @dev Pops the last byte off of a byte array by modifying its length.
+    /// @param b Byte array that will be modified.
+    /// @return The byte that was popped off.
+    function publicPopLastByte(bytes memory b)
+        public
+        pure
+        returns (bytes memory, bytes1 result)
+    {
+        result = b.popLastByte();
+        return (b, result);
+    }
+
+    /// @dev Pops the last 20 bytes off of a byte array by modifying its length.
+    /// @param b Byte array that will be modified.
+    /// @return The 20 byte address that was popped off.
+    function publicPopLast20Bytes(bytes memory b)
+        public
+        pure
+        returns (bytes memory, address result)
+    {
+        result = b.popLast20Bytes();
+        return (b, result);
+    }
+
+    /// @dev Tests equality of two byte arrays.
+    /// @param lhs First byte array to compare.
+    /// @param rhs Second byte array to compare.
+    /// @return True if arrays are the same. False otherwise.
+    function publicEquals(bytes memory lhs, bytes memory rhs)
+        public
+        pure
+        returns (bool equal)
+    {
+        equal = lhs.equals(rhs);
+        return equal;
+    }
+    
+    function publicEqualsPop1(bytes memory lhs, bytes memory rhs)
+        public
+        pure
+        returns (bool equal)
+    {
+        lhs.popLastByte();
+        rhs.popLastByte();
+        equal = lhs.equals(rhs);
+        return equal;
+    }
+
+    /// @dev Performs a deep copy of a byte array onto another byte array of greater than or equal length.
+    /// @param dest Byte array that will be overwritten with source bytes.
+    /// @param source Byte array to copy onto dest bytes.
+    function publicDeepCopyBytes(
+        bytes memory dest,
+        bytes memory source
+    )
+        public
+        pure
+        returns (bytes memory)
+    {
+        LibBytes.deepCopyBytes(dest, source);
+        return dest;
+    }
+
+    /// @dev Reads an address from a position in a byte array.
+    /// @param b Byte array containing an address.
+    /// @param index Index in byte array of address.
+    /// @return address from byte array.
+    function publicReadAddress(
+        bytes memory b,
+        uint256 index
+    )
+        public
+        pure
+        returns (address result)
+    {
+        result = b.readAddress(index);
+        return result;
+    }
+
+    /// @dev Writes an address into a specific position in a byte array.
+    /// @param b Byte array to insert address into.
+    /// @param index Index in byte array of address.
+    /// @param input Address to put into byte array.
+    function publicWriteAddress(
+        bytes memory b,
+        uint256 index,
+        address input
+    )
+        public
+        pure
+        returns (bytes memory)
+    {
+        b.writeAddress(index, input);
+        return b;
+    }
+
+    /// @dev Reads a bytes32 value from a position in a byte array.
+    /// @param b Byte array containing a bytes32 value.
+    /// @param index Index in byte array of bytes32 value.
+    /// @return bytes32 value from byte array.
+    function publicReadBytes32(
+        bytes memory b,
+        uint256 index
+    )
+        public
+        pure
+        returns (bytes32 result)
+    {
+        result = b.readBytes32(index);
+        return result;
+    }
+
+    /// @dev Writes a bytes32 into a specific position in a byte array.
+    /// @param b Byte array to insert <input> into.
+    /// @param index Index in byte array of <input>.
+    /// @param input bytes32 to put into byte array.
+    function publicWriteBytes32(
+        bytes memory b,
+        uint256 index,
+        bytes32 input
+    )
+        public
+        pure
+        returns (bytes memory)
+    {
+        b.writeBytes32(index, input);
+        return b;
+    }
+
+    /// @dev Reads a uint256 value from a position in a byte array.
+    /// @param b Byte array containing a uint256 value.
+    /// @param index Index in byte array of uint256 value.
+    /// @return uint256 value from byte array.
+    function publicReadUint256(
+        bytes memory b,
+        uint256 index
+    )
+        public
+        pure
+        returns (uint256 result)
+    {
+        result = b.readUint256(index);
+        return result;
+    }
+
+    /// @dev Writes a uint256 into a specific position in a byte array.
+    /// @param b Byte array to insert <input> into.
+    /// @param index Index in byte array of <input>.
+    /// @param input uint256 to put into byte array.
+    function publicWriteUint256(
+        bytes memory b,
+        uint256 index,
+        uint256 input
+    )
+        public
+        pure
+        returns (bytes memory)
+    {
+        b.writeUint256(index, input);
+        return b;
+    }
+
+    /// @dev Reads an unpadded bytes4 value from a position in a byte array.
+    /// @param b Byte array containing a bytes4 value.
+    /// @param index Index in byte array of bytes4 value.
+    /// @return bytes4 value from byte array.
+    function publicReadBytes4(
+        bytes memory b,
+        uint256 index
+    )
+        public
+        pure
+        returns (bytes4 result)
+    {
+        result = b.readBytes4(index);
+        return result;
+    }
+
+    /// @dev Reads nested bytes from a specific position.
+    /// @param b Byte array containing nested bytes.
+    /// @param index Index of nested bytes.
+    /// @return result Nested bytes.
+    function publicReadBytesWithLength(
+        bytes memory b,
+        uint256 index
+    )
+        public
+        pure
+        returns (bytes memory result)
+    {
+        result = b.readBytesWithLength(index);
+        return result;
+    }
+
+    /// @dev Inserts bytes at a specific position in a byte array.
+    /// @param b Byte array to insert <input> into.
+    /// @param index Index in byte array of <input>.
+    /// @param input bytes to insert.
+    /// @return b Updated input byte array
+    function publicWriteBytesWithLength(
+        bytes memory b,
+        uint256 index,
+        bytes memory input
+    )
+        public
+        pure
+        returns (bytes memory)
+    {
+        b.writeBytesWithLength(index, input);
+        return b;
+    }
+    
+    /// @dev Copies a block of memory from one location to another.
+    /// @param mem Memory contents we want to apply memCopy to
+    /// @param dest Destination offset into <mem>.
+    /// @param source Source offset into <mem>.
+    /// @param length Length of bytes to copy from <source> to <dest>
+    /// @return mem Memory contents after calling memCopy.
+    function testMemcpy(
+        bytes mem,
+        uint256 dest,
+        uint256 source,
+        uint256 length
+    )
+        public // not external, we need input in memory
+        pure
+        returns (bytes)
+    {
+        // Sanity check. Overflows are not checked.
+        require(source + length <= mem.length);
+        require(dest + length <= mem.length);
+
+        // Get pointer to memory contents
+        uint256 offset = mem.contentAddress();
+
+        // Execute memCopy adjusted for memory array location
+        LibBytes.memCopy(offset + dest, offset + source, length);
+
+        // Return modified memory contents
+        return mem;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
new file mode 100644
index 000000000..010080703
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
@@ -0,0 +1,96 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/libs/LibMath.sol";
+import "../../protocol/Exchange/libs/LibOrder.sol";
+import "../../protocol/Exchange/libs/LibFillResults.sol";
+
+contract TestLibs is 
+    LibMath,
+    LibOrder,
+    LibFillResults
+{
+    function publicGetPartialAmount(
+        uint256 numerator,
+        uint256 denominator,
+        uint256 target)
+        public
+        pure
+        returns (uint256 partialAmount)
+    {
+        partialAmount = getPartialAmount(
+            numerator,
+            denominator,
+            target
+        );
+        return partialAmount;
+    }
+
+    function publicIsRoundingError(
+        uint256 numerator,
+        uint256 denominator,
+        uint256 target)
+        public
+        pure
+        returns (bool isError)
+    {
+        isError = isRoundingError(
+            numerator,
+            denominator,
+            target
+        );
+        return isError;
+    }
+
+    function publicGetOrderHash(Order memory order)
+        public
+        view
+        returns (bytes32 orderHash)
+    {
+        orderHash = getOrderHash(order);
+        return orderHash;
+    }
+
+    function getOrderSchemaHash()
+        public
+        pure
+        returns (bytes32)
+    {
+        return EIP712_ORDER_SCHEMA_HASH;
+    }
+
+    function getDomainSeparatorSchemaHash()
+        public
+        pure
+        returns (bytes32)
+    {
+        return EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH;
+    }
+
+    function publicAddFillResults(FillResults memory totalFillResults, FillResults memory singleFillResults)
+        public
+        pure
+        returns (FillResults memory)
+    {
+        addFillResults(totalFillResults, singleFillResults);
+        return totalFillResults;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/TestSignatureValidator/TestSignatureValidator.sol b/packages/contracts/src/2.0.0/test/TestSignatureValidator/TestSignatureValidator.sol
new file mode 100644
index 000000000..0f84678cf
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/TestSignatureValidator/TestSignatureValidator.sol
@@ -0,0 +1,46 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/MixinSignatureValidator.sol";
+import "../../protocol/Exchange/MixinTransactions.sol";
+
+contract TestSignatureValidator is
+    MixinSignatureValidator,
+    MixinTransactions
+{
+
+    function publicIsValidSignature(
+        bytes32 hash,
+        address signer,
+        bytes memory signature
+    )
+        public
+        view
+        returns (bool isValid)
+    {
+        isValid = isValidSignature(
+            hash,
+            signer,
+            signature
+        );
+        return isValid;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/TestValidator/TestValidator.sol b/packages/contracts/src/2.0.0/test/TestValidator/TestValidator.sol
new file mode 100644
index 000000000..f9271bf7a
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/TestValidator/TestValidator.sol
@@ -0,0 +1,52 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../protocol/Exchange/interfaces/IValidator.sol";
+
+contract TestValidator is 
+    IValidator
+{
+
+    // The single valid signer for this wallet.
+    address VALID_SIGNER;
+
+    /// @dev constructs a new `TestValidator` with a single valid signer.
+    /// @param validSigner The sole, valid signer.
+    constructor (address validSigner) public {
+        VALID_SIGNER = validSigner;
+    }
+
+    /// @dev Verifies that a signature is valid. `signer` must match `VALID_SIGNER`.
+    /// @param hash Message hash that is signed.
+    /// @param signerAddress Address that should have signed the given hash.
+    /// @param signature Proof of signing.
+    /// @return Validity of signature.
+    function isValidSignature(
+        bytes32 hash,
+        address signerAddress,
+        bytes signature
+    )
+        external
+        view
+        returns (bool isValid)
+    {
+        return (signerAddress == VALID_SIGNER);
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/TestWallet/TestWallet.sol b/packages/contracts/src/2.0.0/test/TestWallet/TestWallet.sol
new file mode 100644
index 000000000..17dee9e9c
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/TestWallet/TestWallet.sol
@@ -0,0 +1,65 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+import "../../protocol/Exchange/interfaces/IWallet.sol";
+import "../../utils/LibBytes/LibBytes.sol";
+
+contract TestWallet is 
+    IWallet
+{
+    using LibBytes for bytes;
+
+    string constant LENGTH_65_REQUIRED = "LENGTH_65_REQUIRED";
+
+    // The owner of this wallet.
+    address WALLET_OWNER;
+
+    /// @dev constructs a new `TestWallet` with a single owner.
+    /// @param walletOwner The owner of this wallet.
+    constructor (address walletOwner) public {
+        WALLET_OWNER = walletOwner;
+    }
+
+    /// @dev Validates an EIP712 signature.
+    ///      The signer must match the owner of this wallet.
+    /// @param hash Message hash that is signed.
+    /// @param eip712Signature Proof of signing.
+    /// @return Validity of signature.
+    function isValidSignature(
+        bytes32 hash,
+        bytes eip712Signature
+    )
+        external
+        view
+        returns (bool isValid)
+    {
+        require(
+            eip712Signature.length == 65,
+            LENGTH_65_REQUIRED
+        );
+
+        uint8 v = uint8(eip712Signature[0]);
+        bytes32 r = eip712Signature.readBytes32(1);
+        bytes32 s = eip712Signature.readBytes32(33);
+        address recoveredAddress = ecrecover(hash, v, r, s);
+        isValid = WALLET_OWNER == recoveredAddress;
+        return isValid;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol b/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol
new file mode 100644
index 000000000..8b52858b1
--- /dev/null
+++ b/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol
@@ -0,0 +1,133 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../protocol/Exchange/interfaces/IExchange.sol";
+import "../../protocol/Exchange/libs/LibOrder.sol";
+import "../../utils/Ownable/Ownable.sol";
+
+contract Whitelist is
+    Ownable
+{
+    // Revert reasons
+    string constant MAKER_NOT_WHITELISTED = "MAKER_NOT_WHITELISTED"; // Maker address not whitelisted.
+    string constant TAKER_NOT_WHITELISTED = "TAKER_NOT_WHITELISTED"; // Taker address not whitelisted.
+    string constant INVALID_SENDER = "INVALID_SENDER"; // Sender must equal transaction origin.
+
+    // Mapping of address => whitelist status.
+    mapping (address => bool) public isWhitelisted;
+
+    // Exchange contract.
+    IExchange EXCHANGE;
+
+    byte constant VALIDATOR_SIGNATURE_BYTE = "\x06";
+    bytes TX_ORIGIN_SIGNATURE;
+
+    constructor (address _exchange)
+        public
+    {
+        EXCHANGE = IExchange(_exchange);
+        TX_ORIGIN_SIGNATURE = abi.encodePacked(address(this), VALIDATOR_SIGNATURE_BYTE);
+    }
+
+    /// @dev Adds or removes an address from the whitelist.
+    /// @param target Address to add or remove from whitelist.
+    /// @param isApproved Whitelist status to assign to address.
+    function updateWhitelistStatus(
+        address target,
+        bool isApproved
+    )
+        external
+        onlyOwner
+    {
+        isWhitelisted[target] = isApproved;
+    }
+
+    /// @dev Fills an order using `msg.sender` as the taker.
+    ///      The transaction will revert if both the maker and taker are not whitelisted.
+    ///      Orders should specify this contract as the `senderAddress` in order to gaurantee
+    ///      that both maker and taker have been whitelisted.
+    /// @param order Order struct containing order specifications.
+    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
+    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
+    /// @param orderSignature Proof that order has been created by maker.
+    function fillOrderIfWhitelisted(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount,
+        uint256 salt,
+        bytes memory orderSignature
+    )
+        public
+    {
+        address takerAddress = msg.sender;
+
+        // This contract must be the entry point for the transaction.
+        require(
+            takerAddress == tx.origin,
+            INVALID_SENDER
+        );
+
+        // Check if maker is on the whitelist.
+        require(
+            isWhitelisted[order.makerAddress],
+            MAKER_NOT_WHITELISTED
+        );
+
+        // Check if taker is on the whitelist.
+        require(
+            isWhitelisted[takerAddress],
+            TAKER_NOT_WHITELISTED
+        );
+
+        // Encode arguments into byte array.
+        bytes memory data = abi.encodeWithSelector(
+            EXCHANGE.fillOrder.selector,
+            order,
+            takerAssetFillAmount,
+            orderSignature
+        );
+
+        // Call `fillOrder` via `executeTransaction`.
+        EXCHANGE.executeTransaction(
+            salt,
+            takerAddress,
+            data,
+            TX_ORIGIN_SIGNATURE
+        );
+    }
+
+    /// @dev Verifies signer is same as signer of current Ethereum transaction.
+    ///      NOTE: This function can currently be used to validate signatures coming from outside of this contract.
+    ///      Extra safety checks can be added for a production contract.
+    /// @param signerAddress Address that should have signed the given hash.
+    /// @param signature Proof of signing.
+    /// @return Validity of order signature.
+    function isValidSignature(
+        bytes32 hash,
+        address signerAddress,
+        bytes signature
+    )
+        external
+        view
+        returns (bool isValid)
+    {
+        return signerAddress == tx.origin;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol b/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol
new file mode 100644
index 000000000..b6961a6ec
--- /dev/null
+++ b/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol
@@ -0,0 +1,99 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "./IERC20Token.sol";
+
+contract ERC20Token is IERC20Token {
+
+    string constant INSUFFICIENT_BALANCE = "ERC20_INSUFFICIENT_BALANCE";
+    string constant INSUFFICIENT_ALLOWANCE = "ERC20_INSUFFICIENT_ALLOWANCE";
+    string constant OVERFLOW = "Transfer would result in an overflow.";
+
+    mapping (address => uint256) balances;
+    mapping (address => mapping (address => uint256)) allowed;
+
+    uint256 public totalSupply;
+
+    function transfer(address _to, uint256 _value)
+        public
+        returns (bool)
+    {
+        require(
+            balances[msg.sender] >= _value,
+            INSUFFICIENT_BALANCE
+        );
+        require(
+            balances[_to] + _value >= balances[_to],
+            OVERFLOW
+        );
+        balances[msg.sender] -= _value;
+        balances[_to] += _value;
+        emit Transfer(msg.sender, _to, _value);
+        return true;
+    }
+
+    function transferFrom(address _from, address _to, uint256 _value)
+        public
+        returns (bool)
+    {
+        require(
+            balances[_from] >= _value,
+            INSUFFICIENT_BALANCE
+        );
+        require(
+            allowed[_from][msg.sender] >= _value,
+            INSUFFICIENT_ALLOWANCE
+        );
+        require(
+            balances[_to] + _value >= balances[_to],
+            OVERFLOW
+        );
+        balances[_to] += _value;
+        balances[_from] -= _value;
+        allowed[_from][msg.sender] -= _value;
+        emit Transfer(_from, _to, _value);
+        return true;
+    }
+
+    function approve(address _spender, uint256 _value)
+        public
+        returns (bool)
+    {
+        allowed[msg.sender][_spender] = _value;
+        emit Approval(msg.sender, _spender, _value);
+        return true;
+    }
+
+    function balanceOf(address _owner)
+        public view
+        returns (uint256)
+    {
+        return balances[_owner];
+    }
+
+    function allowance(address _owner, address _spender)
+        public
+        view
+        returns (uint256)
+    {
+        return allowed[_owner][_spender];
+    }
+}
diff --git a/packages/contracts/src/2.0.0/tokens/ERC20Token/IERC20Token.sol b/packages/contracts/src/2.0.0/tokens/ERC20Token/IERC20Token.sol
new file mode 100644
index 000000000..eb879b6a8
--- /dev/null
+++ b/packages/contracts/src/2.0.0/tokens/ERC20Token/IERC20Token.sol
@@ -0,0 +1,73 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+contract IERC20Token {
+
+    /// @notice send `value` token to `to` from `msg.sender`
+    /// @param _to The address of the recipient
+    /// @param _value The amount of token to be transferred
+    /// @return Whether the transfer was successful or not
+    function transfer(address _to, uint256 _value)
+        public
+        returns (bool);
+
+    /// @notice send `value` token to `to` from `from` on the condition it is approved by `from`
+    /// @param _from The address of the sender
+    /// @param _to The address of the recipient
+    /// @param _value The amount of token to be transferred
+    /// @return Whether the transfer was successful or not
+    function transferFrom(address _from, address _to, uint256 _value)
+        public
+        returns (bool);
+    
+    /// @notice `msg.sender` approves `_spender` to spend `_value` tokens
+    /// @param _spender The address of the account able to transfer the tokens
+    /// @param _value The amount of wei to be approved for transfer
+    /// @return Whether the approval was successful or not
+    function approve(address _spender, uint256 _value)
+        public
+        returns (bool);
+
+    /// @param _owner The address from which the balance will be retrieved
+    /// @return The balance
+    function balanceOf(address _owner)
+        public view
+        returns (uint256);
+
+    /// @param _owner The address of the account owning tokens
+    /// @param _spender The address of the account able to transfer the tokens
+    /// @return Amount of remaining tokens allowed to spent
+    function allowance(address _owner, address _spender)
+        public view
+        returns (uint256);
+
+    event Transfer(
+        address indexed _from,
+        address indexed _to,
+        uint256 _value
+    );
+    
+    event Approval(
+        address indexed _owner,
+        address indexed _spender,
+        uint256 _value
+    );
+}
diff --git a/packages/contracts/src/2.0.0/tokens/ERC721Token/ERC721Token.sol b/packages/contracts/src/2.0.0/tokens/ERC721Token/ERC721Token.sol
new file mode 100644
index 000000000..41ba149e3
--- /dev/null
+++ b/packages/contracts/src/2.0.0/tokens/ERC721Token/ERC721Token.sol
@@ -0,0 +1,406 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2016 Smart Contract Solutions, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+pragma solidity ^0.4.24;
+
+import "./IERC721Token.sol";
+import "./IERC721Receiver.sol";
+import "../../utils/SafeMath/SafeMath.sol";
+
+/**
+ * @title ERC721 Non-Fungible Token Standard basic implementation
+ * @dev see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
+ * Modified from https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/token/ERC721/ERC721BasicToken.sol
+ */
+contract ERC721Token is
+    IERC721Token,
+    SafeMath
+{
+    // Equals to `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
+    // which can be also obtained as `ERC721Receiver(0).onERC721Received.selector`
+    bytes4 constant ERC721_RECEIVED = 0xf0b9e5ba;
+
+    // Mapping from token ID to owner
+    mapping (uint256 => address) internal tokenOwner;
+
+    // Mapping from token ID to approved address
+    mapping (uint256 => address) internal tokenApprovals;
+
+    // Mapping from owner to number of owned token
+    mapping (address => uint256) internal ownedTokensCount;
+
+    // Mapping from owner to operator approvals
+    mapping (address => mapping (address => bool)) internal operatorApprovals;
+
+    /**
+    * @dev Guarantees msg.sender is owner of the given token
+    * @param _tokenId uint256 ID of the token to validate its ownership belongs to msg.sender
+    */
+    modifier onlyOwnerOf(uint256 _tokenId) {
+        require(ownerOf(_tokenId) == msg.sender);
+        _;
+    }
+
+    /**
+    * @dev Checks msg.sender can transfer a token, by being owner, approved, or operator
+    * @param _tokenId uint256 ID of the token to validate
+    */
+    modifier canTransfer(uint256 _tokenId) {
+        require(isApprovedOrOwner(msg.sender, _tokenId));
+        _;
+    }
+
+    function ERC721Token(
+        string _name,
+        string _symbol)
+        public
+    {
+        name_ = _name;
+        symbol_ = _symbol;
+    }
+
+    /**
+    * @dev Gets the token name
+    * @return string representing the token name
+    */
+    function name()
+        public
+        view
+        returns (string)
+    {
+        return name_;
+    }
+
+    /**
+    * @dev Gets the token symbol
+    * @return string representing the token symbol
+    */
+    function symbol()
+        public
+        view
+        returns (string)
+    {
+        return symbol_;
+    }
+
+    /**
+    * @dev Gets the balance of the specified address
+    * @param _owner address to query the balance of
+    * @return uint256 representing the amount owned by the passed address
+    */
+    function balanceOf(address _owner)
+        public
+        view
+        returns (uint256)
+    {
+        require(_owner != address(0));
+        return ownedTokensCount[_owner];
+    }
+
+    /**
+    * @dev Gets the owner of the specified token ID
+    * @param _tokenId uint256 ID of the token to query the owner of
+    * @return owner address currently marked as the owner of the given token ID
+    */
+    function ownerOf(uint256 _tokenId)
+        public
+        view
+        returns (address)
+    {
+        address owner = tokenOwner[_tokenId];
+        require(owner != address(0));
+        return owner;
+    }
+
+    /**
+    * @dev Returns whether the specified token exists
+    * @param _tokenId uint256 ID of the token to query the existance of
+    * @return whether the token exists
+    */
+    function exists(uint256 _tokenId)
+        public
+        view
+        returns (bool)
+    {
+        address owner = tokenOwner[_tokenId];
+        return owner != address(0);
+    }
+
+    /**
+    * @dev Approves another address to transfer the given token ID
+    * @dev The zero address indicates there is no approved address.
+    * @dev There can only be one approved address per token at a given time.
+    * @dev Can only be called by the token owner or an approved operator.
+    * @param _to address to be approved for the given token ID
+    * @param _tokenId uint256 ID of the token to be approved
+    */
+    function approve(address _to, uint256 _tokenId)
+        public
+    {
+        address owner = ownerOf(_tokenId);
+        require(_to != owner);
+        require(msg.sender == owner || isApprovedForAll(owner, msg.sender));
+
+        if (getApproved(_tokenId) != address(0) || _to != address(0)) {
+            tokenApprovals[_tokenId] = _to;
+            emit Approval(owner, _to, _tokenId);
+        }
+    }
+
+    /**
+    * @dev Gets the approved address for a token ID, or zero if no address set
+    * @param _tokenId uint256 ID of the token to query the approval of
+    * @return address currently approved for a the given token ID
+    */
+    function getApproved(uint256 _tokenId)
+        public
+        view
+        returns (address)
+    {
+        return tokenApprovals[_tokenId];
+    }
+
+    /**
+    * @dev Sets or unsets the approval of a given operator
+    * @dev An operator is allowed to transfer all tokens of the sender on their behalf
+    * @param _to operator address to set the approval
+    * @param _approved representing the status of the approval to be set
+    */
+    function setApprovalForAll(address _to, bool _approved)
+        public
+    {
+        require(_to != msg.sender);
+        operatorApprovals[msg.sender][_to] = _approved;
+        emit ApprovalForAll(msg.sender, _to, _approved);
+    }
+
+    /**
+    * @dev Tells whether an operator is approved by a given owner
+    * @param _owner owner address which you want to query the approval of
+    * @param _operator operator address which you want to query the approval of
+    * @return bool whether the given operator is approved by the given owner
+    */
+    function isApprovedForAll(address _owner, address _operator)
+        public
+        view
+        returns (bool)
+    {
+        return operatorApprovals[_owner][_operator];
+    }
+
+    /**
+    * @dev Transfers the ownership of a given token ID to another address
+    * @dev Usage of this method is discouraged, use `safeTransferFrom` whenever possible
+    * @dev Requires the msg sender to be the owner, approved, or operator
+    * @param _from current owner of the token
+    * @param _to address to receive the ownership of the given token ID
+    * @param _tokenId uint256 ID of the token to be transferred
+    */
+    function transferFrom(address _from, address _to, uint256 _tokenId)
+        public
+        canTransfer(_tokenId)
+    {
+        require(_from != address(0));
+        require(_to != address(0));
+
+        clearApproval(_from, _tokenId);
+        removeTokenFrom(_from, _tokenId);
+        addTokenTo(_to, _tokenId);
+
+        emit Transfer(_from, _to, _tokenId);
+    }
+
+    /**
+    * @dev Safely transfers the ownership of a given token ID to another address
+    * @dev If the target address is a contract, it must implement `onERC721Received`,
+    *  which is called upon a safe transfer, and return the magic value
+    *  `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`; otherwise,
+    *  the transfer is reverted.
+    * @dev Requires the msg sender to be the owner, approved, or operator
+    * @param _from current owner of the token
+    * @param _to address to receive the ownership of the given token ID
+    * @param _tokenId uint256 ID of the token to be transferred
+    */
+    function safeTransferFrom(
+        address _from,
+        address _to,
+        uint256 _tokenId)
+        public
+        canTransfer(_tokenId)
+    {
+        // solium-disable-next-line arg-overflow
+        safeTransferFrom(_from, _to, _tokenId, "");
+    }
+
+    /**
+    * @dev Safely transfers the ownership of a given token ID to another address
+    * @dev If the target address is a contract, it must implement `onERC721Received`,
+    *  which is called upon a safe transfer, and return the magic value
+    *  `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`; otherwise,
+    *  the transfer is reverted.
+    * @dev Requires the msg sender to be the owner, approved, or operator
+    * @param _from current owner of the token
+    * @param _to address to receive the ownership of the given token ID
+    * @param _tokenId uint256 ID of the token to be transferred
+    * @param _data bytes data to send along with a safe transfer check
+    */
+    function safeTransferFrom(
+        address _from,
+        address _to,
+        uint256 _tokenId,
+        bytes _data)
+        public
+        canTransfer(_tokenId)
+    {
+        transferFrom(_from, _to, _tokenId);
+        // solium-disable-next-line arg-overflow
+        require(checkAndCallSafeTransfer(_from, _to, _tokenId, _data));
+    }
+
+    /**
+    * @dev Returns whether the given spender can transfer a given token ID
+    * @param _spender address of the spender to query
+    * @param _tokenId uint256 ID of the token to be transferred
+    * @return bool whether the msg.sender is approved for the given token ID,
+    *  is an operator of the owner, or is the owner of the token
+    */
+    function isApprovedOrOwner(address _spender, uint256 _tokenId)
+        internal
+        view
+        returns (bool)
+    {
+        address owner = ownerOf(_tokenId);
+        return _spender == owner || getApproved(_tokenId) == _spender || isApprovedForAll(owner, _spender);
+    }
+
+    /**
+    * @dev Internal function to mint a new token
+    * @dev Reverts if the given token ID already exists
+    * @param _to The address that will own the minted token
+    * @param _tokenId uint256 ID of the token to be minted by the msg.sender
+    */
+    function _mint(address _to, uint256 _tokenId)
+        internal
+    {
+        require(_to != address(0));
+        addTokenTo(_to, _tokenId);
+        emit Transfer(address(0), _to, _tokenId);
+    }
+
+    /**
+    * @dev Internal function to burn a specific token
+    * @dev Reverts if the token does not exist
+    * @param _tokenId uint256 ID of the token being burned by the msg.sender
+    */
+    function _burn(address _owner, uint256 _tokenId)
+        internal
+    {
+        clearApproval(_owner, _tokenId);
+        removeTokenFrom(_owner, _tokenId);
+        emit Transfer(_owner, address(0), _tokenId);
+    }
+
+    /**
+    * @dev Internal function to clear current approval of a given token ID
+    * @dev Reverts if the given address is not indeed the owner of the token
+    * @param _owner owner of the token
+    * @param _tokenId uint256 ID of the token to be transferred
+    */
+    function clearApproval(address _owner, uint256 _tokenId)
+        internal
+    {
+        require(ownerOf(_tokenId) == _owner);
+        if (tokenApprovals[_tokenId] != address(0)) {
+            tokenApprovals[_tokenId] = address(0);
+            emit Approval(_owner, address(0), _tokenId);
+        }
+    }
+
+    /**
+    * @dev Internal function to add a token ID to the list of a given address
+    * @param _to address representing the new owner of the given token ID
+    * @param _tokenId uint256 ID of the token to be added to the tokens list of the given address
+    */
+    function addTokenTo(address _to, uint256 _tokenId)
+        internal
+    {
+        require(tokenOwner[_tokenId] == address(0));
+        tokenOwner[_tokenId] = _to;
+        ownedTokensCount[_to] = safeAdd(ownedTokensCount[_to], 1);
+    }
+
+    /**
+    * @dev Internal function to remove a token ID from the list of a given address
+    * @param _from address representing the previous owner of the given token ID
+    * @param _tokenId uint256 ID of the token to be removed from the tokens list of the given address
+    */
+    function removeTokenFrom(address _from, uint256 _tokenId)
+        internal
+    {
+        require(ownerOf(_tokenId) == _from);
+        ownedTokensCount[_from] = safeSub(ownedTokensCount[_from], 1);
+        tokenOwner[_tokenId] = address(0);
+    }
+
+    /**
+    * @dev Internal function to invoke `onERC721Received` on a target address
+    * @dev The call is not executed if the target address is not a contract
+    * @param _from address representing the previous owner of the given token ID
+    * @param _to target address that will receive the tokens
+    * @param _tokenId uint256 ID of the token to be transferred
+    * @param _data bytes optional data to send along with the call
+    * @return whether the call correctly returned the expected magic value
+    */
+    function checkAndCallSafeTransfer(
+        address _from,
+        address _to,
+        uint256 _tokenId,
+        bytes _data)
+        internal
+        returns (bool)
+    {
+        if (!isContract(_to)) {
+            return true;
+        }
+        bytes4 retval = IERC721Receiver(_to).onERC721Received(_from, _tokenId, _data);
+        return (retval == ERC721_RECEIVED);
+    }
+
+    function isContract(address addr)
+        internal
+        view
+        returns (bool)
+    {
+        uint256 size;
+        // XXX Currently there is no better way to check if there is a contract in an address
+        // than to check the size of the code at that address.
+        // See https://ethereum.stackexchange.com/a/14016/36603
+        // for more details about how this works.
+        // TODO Check this again before the Serenity release, because all addresses will be
+        // contracts then.
+        assembly { size := extcodesize(addr) }  // solium-disable-line security/no-inline-assembly
+        return size > 0;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Receiver.sol b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Receiver.sol
new file mode 100644
index 000000000..b0fff3c90
--- /dev/null
+++ b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Receiver.sol
@@ -0,0 +1,60 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2016 Smart Contract Solutions, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+pragma solidity ^0.4.24;
+
+/**
+ * @title ERC721 token receiver interface
+ * @dev Interface for any contract that wants to support safeTransfers
+ *      rom ERC721 asset contracts.
+ * Modified from https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/token/ERC721/ERC721Receiver.sol
+ */
+contract IERC721Receiver {
+    /**
+    * @dev Magic value to be returned upon successful reception of an NFT
+    *  Equals to `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`,
+    *  which can be also obtained as `ERC721Receiver(0).onERC721Received.selector`
+    */
+    bytes4 constant ERC721_RECEIVED = 0xf0b9e5ba;
+
+    /**
+    * @notice Handle the receipt of an NFT
+    * @dev The ERC721 smart contract calls this function on the recipient
+    *  after a `safetransfer`. This function MAY throw to revert and reject the
+    *  transfer. This function MUST use 50,000 gas or less. Return of other
+    *  than the magic value MUST result in the transaction being reverted.
+    *  Note: the contract address is always the message sender.
+    * @param _from The sending address
+    * @param _tokenId The NFT identifier which is being transfered
+    * @param _data Additional data with no specified format
+    * @return `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
+    */
+    function onERC721Received(
+        address _from,
+        uint256 _tokenId,
+        bytes _data)
+        public
+        returns (bytes4);
+}
diff --git a/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Token.sol b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Token.sol
new file mode 100644
index 000000000..345712d67
--- /dev/null
+++ b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Token.sol
@@ -0,0 +1,105 @@
+/*
+The MIT License (MIT)
+
+Copyright (c) 2016 Smart Contract Solutions, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+pragma solidity ^0.4.24;
+
+/**
+ * @title ERC721 Non-Fungible Token Standard basic interface
+ * @dev see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
+ * Modified from https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/token/ERC721/ERC721Basic.sol
+ */
+contract IERC721Token {
+    string internal name_;
+    string internal symbol_;
+
+    event Transfer(
+        address indexed _from,
+        address indexed _to,
+        uint256 _tokenId
+    );
+    event Approval(
+        address indexed _owner,
+        address indexed _approved,
+        uint256 _tokenId
+    );
+    event ApprovalForAll(
+        address indexed _owner,
+        address indexed _operator,
+        bool _approved
+    );
+
+    function name()
+        public
+        view
+        returns (string);
+    function symbol()
+        public
+        view
+        returns (string);
+
+    function balanceOf(address _owner)
+        public
+        view
+        returns (uint256 _balance);
+    function ownerOf(uint256 _tokenId)
+        public
+        view
+        returns (address _owner);
+    function exists(uint256 _tokenId)
+        public
+        view
+        returns (bool _exists);
+
+    function approve(address _to, uint256 _tokenId)
+        public;
+    function getApproved(uint256 _tokenId)
+        public
+        view
+        returns (address _operator);
+
+    function setApprovalForAll(address _operator, bool _approved)
+        public;
+    function isApprovedForAll(address _owner, address _operator)
+        public
+        view
+        returns (bool);
+
+    function transferFrom(
+        address _from,
+        address _to,
+        uint256 _tokenId)
+        public;
+    function safeTransferFrom(
+        address _from,
+        address _to,
+        uint256 _tokenId)
+        public;
+    function safeTransferFrom(
+        address _from,
+        address _to,
+        uint256 _tokenId,
+        bytes _data)
+        public;
+}
diff --git a/packages/contracts/src/2.0.0/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol b/packages/contracts/src/2.0.0/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
new file mode 100644
index 000000000..f62602ab3
--- /dev/null
+++ b/packages/contracts/src/2.0.0/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
@@ -0,0 +1,58 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../ERC20Token/ERC20Token.sol";
+
+contract UnlimitedAllowanceToken is ERC20Token {
+
+    uint256 constant MAX_UINT = 2**256 - 1;
+
+    /// @dev ERC20 transferFrom, modified such that an allowance of MAX_UINT represents an unlimited allowance. See https://github.com/ethereum/EIPs/issues/717
+    /// @param _from Address to transfer from.
+    /// @param _to Address to transfer to.
+    /// @param _value Amount to transfer.
+    /// @return Success of transfer.
+    function transferFrom(address _from, address _to, uint256 _value)
+        public
+        returns (bool)
+    {
+        uint256 allowance = allowed[_from][msg.sender];
+        require(
+            balances[_from] >= _value,
+            INSUFFICIENT_BALANCE
+        );
+        require(
+            allowance >= _value,
+            INSUFFICIENT_ALLOWANCE
+        );
+        require(
+            balances[_to] + _value >= balances[_to],
+            OVERFLOW
+        );
+        balances[_to] += _value;
+        balances[_from] -= _value;
+        if (allowance < MAX_UINT) {
+            allowed[_from][msg.sender] -= _value;
+        }
+        emit Transfer(_from, _to, _value);
+        return true;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/tokens/WETH9/WETH9.sol b/packages/contracts/src/2.0.0/tokens/WETH9/WETH9.sol
new file mode 100644
index 000000000..733ca414b
--- /dev/null
+++ b/packages/contracts/src/2.0.0/tokens/WETH9/WETH9.sol
@@ -0,0 +1,756 @@
+// Copyright (C) 2015, 2016, 2017 Dapphub
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+pragma solidity ^0.4.18;
+
+contract WETH9 {
+    string public name     = "Wrapped Ether";
+    string public symbol   = "WETH";
+    uint8  public decimals = 18;
+
+    event  Approval(address indexed src, address indexed guy, uint wad);
+    event  Transfer(address indexed src, address indexed dst, uint wad);
+    event  Deposit(address indexed dst, uint wad);
+    event  Withdrawal(address indexed src, uint wad);
+
+    mapping (address => uint)                       public  balanceOf;
+    mapping (address => mapping (address => uint))  public  allowance;
+
+    function() public payable {
+        deposit();
+    }
+    function deposit() public payable {
+        balanceOf[msg.sender] += msg.value;
+        Deposit(msg.sender, msg.value);
+    }
+    function withdraw(uint wad) public {
+        require(balanceOf[msg.sender] >= wad);
+        balanceOf[msg.sender] -= wad;
+        msg.sender.transfer(wad);
+        Withdrawal(msg.sender, wad);
+    }
+
+    function totalSupply() public view returns (uint) {
+        return this.balance;
+    }
+
+    function approve(address guy, uint wad) public returns (bool) {
+        allowance[msg.sender][guy] = wad;
+        Approval(msg.sender, guy, wad);
+        return true;
+    }
+
+    function transfer(address dst, uint wad) public returns (bool) {
+        return transferFrom(msg.sender, dst, wad);
+    }
+
+    function transferFrom(address src, address dst, uint wad)
+        public
+        returns (bool)
+    {
+        require(balanceOf[src] >= wad);
+
+        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
+            require(allowance[src][msg.sender] >= wad);
+            allowance[src][msg.sender] -= wad;
+        }
+
+        balanceOf[src] -= wad;
+        balanceOf[dst] += wad;
+
+        Transfer(src, dst, wad);
+
+        return true;
+    }
+}
+
+
+/*
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.  We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors.  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights.  Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received.  You must make sure that they, too, receive
+or can get the source code.  And you must show them these terms so they
+know their rights.
+
+  Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+  For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software.  For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+  Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so.  This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software.  The systematic
+pattern of such abuse occurs in the area of products for individuals to
+use, which is precisely where it is most unacceptable.  Therefore, we
+have designed this version of the GPL to prohibit the practice for those
+products.  If such problems arise substantially in other domains, we
+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+  Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary.  To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                       TERMS AND CONDITIONS
+
+  0. Definitions.
+
+  "This License" refers to version 3 of the GNU General Public License.
+
+  "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+  "The Program" refers to any copyrightable work licensed under this
+License.  Each licensee is addressed as "you".  "Licensees" and
+"recipients" may be individuals or organizations.
+
+  To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy.  The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+  A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+  To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy.  Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+  To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies.  Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+  An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License.  If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+  1. Source Code.
+
+  The "source code" for a work means the preferred form of the work
+for making modifications to it.  "Object code" means any non-source
+form of a work.
+
+  A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+  The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form.  A
+"Major Component", in this context, means a major essential component
+(kernel, window system, and so on) of the specific operating system
+(if any) on which the executable work runs, or a compiler used to
+produce the work, or an object code interpreter used to run it.
+
+  The "Corresponding Source" for a work in object code form means all
+the source code needed to generate, install, and (for an executable
+work) run the object code and to modify the work, including scripts to
+control those activities.  However, it does not include the work's
+System Libraries, or general-purpose tools or generally available free
+programs which are used unmodified in performing those activities but
+which are not part of the work.  For example, Corresponding Source
+includes interface definition files associated with source files for
+the work, and the source code for shared libraries and dynamically
+linked subprograms that the work is specifically designed to require,
+such as by intimate data communication or control flow between those
+subprograms and other parts of the work.
+
+  The Corresponding Source need not include anything that users
+can regenerate automatically from other parts of the Corresponding
+Source.
+
+  The Corresponding Source for a work in source code form is that
+same work.
+
+  2. Basic Permissions.
+
+  All rights granted under this License are granted for the term of
+copyright on the Program, and are irrevocable provided the stated
+conditions are met.  This License explicitly affirms your unlimited
+permission to run the unmodified Program.  The output from running a
+covered work is covered by this License only if the output, given its
+content, constitutes a covered work.  This License acknowledges your
+rights of fair use or other equivalent, as provided by copyright law.
+
+  You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force.  You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
+with facilities for running those works, provided that you comply with
+the terms of this License in conveying all material for which you do
+not control copyright.  Those thus making or running the covered works
+for you must do so exclusively on your behalf, under your direction
+and control, on terms that prohibit them from making any copies of
+your copyrighted material outside their relationship with you.
+
+  Conveying under any other circumstances is permitted solely under
+the conditions stated below.  Sublicensing is not allowed; section 10
+makes it unnecessary.
+
+  3. Protecting Users' Legal Rights From Anti-Circumvention Law.
+
+  No covered work shall be deemed part of an effective technological
+measure under any applicable law fulfilling obligations under article
+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+  When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
+is effected by exercising rights under this License with respect to
+the covered work, and you disclaim any intention to limit operation or
+modification of the work as a means of enforcing, against the work's
+users, your or third parties' legal rights to forbid circumvention of
+technological measures.
+
+  4. Conveying Verbatim Copies.
+
+  You may convey verbatim copies of the Program's source code as you
+receive it, in any medium, provided that you conspicuously and
+appropriately publish on each copy an appropriate copyright notice;
+keep intact all notices stating that this License and any
+non-permissive terms added in accord with section 7 apply to the code;
+keep intact all notices of the absence of any warranty; and give all
+recipients a copy of this License along with the Program.
+
+  You may charge any price or no price for each copy that you convey,
+and you may offer support or warranty protection for a fee.
+
+  5. Conveying Modified Source Versions.
+
+  You may convey a work based on the Program, or the modifications to
+produce it from the Program, in the form of source code under the
+terms of section 4, provided that you also meet all of these conditions:
+
+    a) The work must carry prominent notices stating that you modified
+    it, and giving a relevant date.
+
+    b) The work must carry prominent notices stating that it is
+    released under this License and any conditions added under section
+    7.  This requirement modifies the requirement in section 4 to
+    "keep intact all notices".
+
+    c) You must license the entire work, as a whole, under this
+    License to anyone who comes into possession of a copy.  This
+    License will therefore apply, along with any applicable section 7
+    additional terms, to the whole of the work, and all its parts,
+    regardless of how they are packaged.  This License gives no
+    permission to license the work in any other way, but it does not
+    invalidate such permission if you have separately received it.
+
+    d) If the work has interactive user interfaces, each must display
+    Appropriate Legal Notices; however, if the Program has interactive
+    interfaces that do not display Appropriate Legal Notices, your
+    work need not make them do so.
+
+  A compilation of a covered work with other separate and independent
+works, which are not by their nature extensions of the covered work,
+and which are not combined with it such as to form a larger program,
+in or on a volume of a storage or distribution medium, is called an
+"aggregate" if the compilation and its resulting copyright are not
+used to limit the access or legal rights of the compilation's users
+beyond what the individual works permit.  Inclusion of a covered work
+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
+
+  6. Conveying Non-Source Forms.
+
+  You may convey a covered work in object code form under the terms
+of sections 4 and 5, provided that you also convey the
+machine-readable Corresponding Source under the terms of this License,
+in one of these ways:
+
+    a) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by the
+    Corresponding Source fixed on a durable physical medium
+    customarily used for software interchange.
+
+    b) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by a
+    written offer, valid for at least three years and valid for as
+    long as you offer spare parts or customer support for that product
+    model, to give anyone who possesses the object code either (1) a
+    copy of the Corresponding Source for all the software in the
+    product that is covered by this License, on a durable physical
+    medium customarily used for software interchange, for a price no
+    more than your reasonable cost of physically performing this
+    conveying of source, or (2) access to copy the
+    Corresponding Source from a network server at no charge.
+
+    c) Convey individual copies of the object code with a copy of the
+    written offer to provide the Corresponding Source.  This
+    alternative is allowed only occasionally and noncommercially, and
+    only if you received the object code with such an offer, in accord
+    with subsection 6b.
+
+    d) Convey the object code by offering access from a designated
+    place (gratis or for a charge), and offer equivalent access to the
+    Corresponding Source in the same way through the same place at no
+    further charge.  You need not require recipients to copy the
+    Corresponding Source along with the object code.  If the place to
+    copy the object code is a network server, the Corresponding Source
+    may be on a different server (operated by you or a third party)
+    that supports equivalent copying facilities, provided you maintain
+    clear directions next to the object code saying where to find the
+    Corresponding Source.  Regardless of what server hosts the
+    Corresponding Source, you remain obligated to ensure that it is
+    available for as long as needed to satisfy these requirements.
+
+    e) Convey the object code using peer-to-peer transmission, provided
+    you inform other peers where the object code and Corresponding
+    Source of the work are being offered to the general public at no
+    charge under subsection 6d.
+
+  A separable portion of the object code, whose source code is excluded
+from the Corresponding Source as a System Library, need not be
+included in conveying the object code work.
+
+  A "User Product" is either (1) a "consumer product", which means any
+tangible personal property which is normally used for personal, family,
+or household purposes, or (2) anything designed or sold for incorporation
+into a dwelling.  In determining whether a product is a consumer product,
+doubtful cases shall be resolved in favor of coverage.  For a particular
+product received by a particular user, "normally used" refers to a
+typical or common use of that class of product, regardless of the status
+of the particular user or of the way in which the particular user
+actually uses, or expects or is expected to use, the product.  A product
+is a consumer product regardless of whether the product has substantial
+commercial, industrial or non-consumer uses, unless such uses represent
+the only significant mode of use of the product.
+
+  "Installation Information" for a User Product means any methods,
+procedures, authorization keys, or other information required to install
+and execute modified versions of a covered work in that User Product from
+a modified version of its Corresponding Source.  The information must
+suffice to ensure that the continued functioning of the modified object
+code is in no case prevented or interfered with solely because
+modification has been made.
+
+  If you convey an object code work under this section in, or with, or
+specifically for use in, a User Product, and the conveying occurs as
+part of a transaction in which the right of possession and use of the
+User Product is transferred to the recipient in perpetuity or for a
+fixed term (regardless of how the transaction is characterized), the
+Corresponding Source conveyed under this section must be accompanied
+by the Installation Information.  But this requirement does not apply
+if neither you nor any third party retains the ability to install
+modified object code on the User Product (for example, the work has
+been installed in ROM).
+
+  The requirement to provide Installation Information does not include a
+requirement to continue to provide support service, warranty, or updates
+for a work that has been modified or installed by the recipient, or for
+the User Product in which it has been modified or installed.  Access to a
+network may be denied when the modification itself materially and
+adversely affects the operation of the network or violates the rules and
+protocols for communication across the network.
+
+  Corresponding Source conveyed, and Installation Information provided,
+in accord with this section must be in a format that is publicly
+documented (and with an implementation available to the public in
+source code form), and must require no special password or key for
+unpacking, reading or copying.
+
+  7. Additional Terms.
+
+  "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law.  If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+  When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
+it.  (Additional permissions may be written to require their own
+removal in certain cases when you modify the work.)  You may place
+additional permissions on material, added by you to a covered work,
+for which you have or can give appropriate copyright permission.
+
+  Notwithstanding any other provision of this License, for material you
+add to a covered work, you may (if authorized by the copyright holders of
+that material) supplement the terms of this License with terms:
+
+    a) Disclaiming warranty or limiting liability differently from the
+    terms of sections 15 and 16 of this License; or
+
+    b) Requiring preservation of specified reasonable legal notices or
+    author attributions in that material or in the Appropriate Legal
+    Notices displayed by works containing it; or
+
+    c) Prohibiting misrepresentation of the origin of that material, or
+    requiring that modified versions of such material be marked in
+    reasonable ways as different from the original version; or
+
+    d) Limiting the use for publicity purposes of names of licensors or
+    authors of the material; or
+
+    e) Declining to grant rights under trademark law for use of some
+    trade names, trademarks, or service marks; or
+
+    f) Requiring indemnification of licensors and authors of that
+    material by anyone who conveys the material (or modified versions of
+    it) with contractual assumptions of liability to the recipient, for
+    any liability that these contractual assumptions directly impose on
+    those licensors and authors.
+
+  All other non-permissive additional terms are considered "further
+restrictions" within the meaning of section 10.  If the Program as you
+received it, or any part of it, contains a notice stating that it is
+governed by this License along with a term that is a further
+restriction, you may remove that term.  If a license document contains
+a further restriction but permits relicensing or conveying under this
+License, you may add to a covered work material governed by the terms
+of that license document, provided that the further restriction does
+not survive such relicensing or conveying.
+
+  If you add terms to a covered work in accord with this section, you
+must place, in the relevant source files, a statement of the
+additional terms that apply to those files, or a notice indicating
+where to find the applicable terms.
+
+  Additional terms, permissive or non-permissive, may be stated in the
+form of a separately written license, or stated as exceptions;
+the above requirements apply either way.
+
+  8. Termination.
+
+  You may not propagate or modify a covered work except as expressly
+provided under this License.  Any attempt otherwise to propagate or
+modify it is void, and will automatically terminate your rights under
+this License (including any patent licenses granted under the third
+paragraph of section 11).
+
+  However, if you cease all violation of this License, then your
+license from a particular copyright holder is reinstated (a)
+provisionally, unless and until the copyright holder explicitly and
+finally terminates your license, and (b) permanently, if the copyright
+holder fails to notify you of the violation by some reasonable means
+prior to 60 days after the cessation.
+
+  Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+  Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License.  If your rights have been terminated and not permanently
+reinstated, you do not qualify to receive new licenses for the same
+material under section 10.
+
+  9. Acceptance Not Required for Having Copies.
+
+  You are not required to accept this License in order to receive or
+run a copy of the Program.  Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance.  However,
+nothing other than this License grants you permission to propagate or
+modify any covered work.  These actions infringe copyright if you do
+not accept this License.  Therefore, by modifying or propagating a
+covered work, you indicate your acceptance of this License to do so.
+
+  10. Automatic Licensing of Downstream Recipients.
+
+  Each time you convey a covered work, the recipient automatically
+receives a license from the original licensors, to run, modify and
+propagate that work, subject to this License.  You are not responsible
+for enforcing compliance by third parties with this License.
+
+  An "entity transaction" is a transaction transferring control of an
+organization, or substantially all assets of one, or subdividing an
+organization, or merging organizations.  If propagation of a covered
+work results from an entity transaction, each party to that
+transaction who receives a copy of the work also receives whatever
+licenses to the work the party's predecessor in interest had or could
+give under the previous paragraph, plus a right to possession of the
+Corresponding Source of the work from the predecessor in interest, if
+the predecessor has it or can get it with reasonable efforts.
+
+  You may not impose any further restrictions on the exercise of the
+rights granted or affirmed under this License.  For example, you may
+not impose a license fee, royalty, or other charge for exercise of
+rights granted under this License, and you may not initiate litigation
+(including a cross-claim or counterclaim in a lawsuit) alleging that
+any patent claim is infringed by making, using, selling, offering for
+sale, or importing the Program or any portion of it.
+
+  11. Patents.
+
+  A "contributor" is a copyright holder who authorizes use under this
+License of the Program or a work on which the Program is based.  The
+work thus licensed is called the contributor's "contributor version".
+
+  A contributor's "essential patent claims" are all patent claims
+owned or controlled by the contributor, whether already acquired or
+hereafter acquired, that would be infringed by some manner, permitted
+by this License, of making, using, or selling its contributor version,
+but do not include claims that would be infringed only as a
+consequence of further modification of the contributor version.  For
+purposes of this definition, "control" includes the right to grant
+patent sublicenses in a manner consistent with the requirements of
+this License.
+
+  Each contributor grants you a non-exclusive, worldwide, royalty-free
+patent license under the contributor's essential patent claims, to
+make, use, sell, offer for sale, import and otherwise run, modify and
+propagate the contents of its contributor version.
+
+  In the following three paragraphs, a "patent license" is any express
+agreement or commitment, however denominated, not to enforce a patent
+(such as an express permission to practice a patent or covenant not to
+sue for patent infringement).  To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+  If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients.  "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+  If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+  A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License.  You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Use with the GNU Affero General Public License.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.
+
+*/
diff --git a/packages/contracts/src/2.0.0/tokens/ZRXToken/ZRXToken.sol b/packages/contracts/src/2.0.0/tokens/ZRXToken/ZRXToken.sol
new file mode 100644
index 000000000..2e5b61e0b
--- /dev/null
+++ b/packages/contracts/src/2.0.0/tokens/ZRXToken/ZRXToken.sol
@@ -0,0 +1,33 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.11;
+
+import { UnlimitedAllowanceToken_v1 as UnlimitedAllowanceToken } from "../../../1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol";
+
+contract ZRXToken is UnlimitedAllowanceToken {
+
+    uint8 constant public decimals = 18;
+    uint public totalSupply = 10**27; // 1 billion tokens, 18 decimal places
+    string constant public name = "0x Protocol Token";
+    string constant public symbol = "ZRX";
+
+    function ZRXToken() {
+        balances[msg.sender] = totalSupply;
+    }
+}
diff --git a/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol b/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol
new file mode 100644
index 000000000..78b1ddf7c
--- /dev/null
+++ b/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol
@@ -0,0 +1,545 @@
+/*
+
+  Copyright 2018 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.4.24;
+
+library LibBytes {
+
+    using LibBytes for bytes;
+
+    /// @dev Gets the memory address for a byte array.
+    /// @param input Byte array to lookup.
+    /// @return memoryAddress Memory address of byte array. This
+    ///         points to the header of the byte array which contains
+    ///         the length.
+    function rawAddress(bytes memory input)
+        internal
+        pure
+        returns (uint256 memoryAddress)
+    {
+        assembly {
+            memoryAddress := input
+        }
+        return memoryAddress;
+    }
+    
+    /// @dev Gets the memory address for the contents of a byte array.
+    /// @param input Byte array to lookup.
+    /// @return memoryAddress Memory address of the contents of the byte array.
+    function contentAddress(bytes memory input)
+        internal
+        pure
+        returns (uint256 memoryAddress)
+    {
+        assembly {
+            memoryAddress := add(input, 32)
+        }
+        return memoryAddress;
+    }
+
+    /// @dev Copies `length` bytes from memory location `source` to `dest`.
+    /// @param dest memory address to copy bytes to.
+    /// @param source memory address to copy bytes from.
+    /// @param length number of bytes to copy.
+    function memCopy(
+        uint256 dest,
+        uint256 source,
+        uint256 length
+    )
+        internal
+        pure
+    {
+        if (length < 32) {
+            // Handle a partial word by reading destination and masking
+            // off the bits we are interested in.
+            // This correctly handles overlap, zero lengths and source == dest
+            assembly {
+                let mask := sub(exp(256, sub(32, length)), 1)
+                let s := and(mload(source), not(mask))
+                let d := and(mload(dest), mask)
+                mstore(dest, or(s, d))
+            }
+        } else {
+            // Skip the O(length) loop when source == dest.
+            if (source == dest) {
+                return;
+            }
+
+            // For large copies we copy whole words at a time. The final
+            // word is aligned to the end of the range (instead of after the
+            // previous) to handle partial words. So a copy will look like this:
+            //
+            //  ####
+            //      ####
+            //          ####
+            //            ####
+            //
+            // We handle overlap in the source and destination range by
+            // changing the copying direction. This prevents us from
+            // overwriting parts of source that we still need to copy.
+            //
+            // This correctly handles source == dest
+            //
+            if (source > dest) {
+                assembly {
+                    // We subtract 32 from `sEnd` and `dEnd` because it
+                    // is easier to compare with in the loop, and these
+                    // are also the addresses we need for copying the
+                    // last bytes.
+                    length := sub(length, 32)
+                    let sEnd := add(source, length)
+                    let dEnd := add(dest, length)
+
+                    // Remember the last 32 bytes of source
+                    // This needs to be done here and not after the loop
+                    // because we may have overwritten the last bytes in
+                    // source already due to overlap.
+                    let last := mload(sEnd)
+
+                    // Copy whole words front to back
+                    // Note: the first check is always true,
+                    // this could have been a do-while loop.
+                    for {} lt(source, sEnd) {} {
+                        mstore(dest, mload(source))
+                        source := add(source, 32)
+                        dest := add(dest, 32)
+                    }
+                    
+                    // Write the last 32 bytes
+                    mstore(dEnd, last)
+                }
+            } else {
+                assembly {
+                    // We subtract 32 from `sEnd` and `dEnd` because those
+                    // are the starting points when copying a word at the end.
+                    length := sub(length, 32)
+                    let sEnd := add(source, length)
+                    let dEnd := add(dest, length)
+
+                    // Remember the first 32 bytes of source
+                    // This needs to be done here and not after the loop
+                    // because we may have overwritten the first bytes in
+                    // source already due to overlap.
+                    let first := mload(source)
+
+                    // Copy whole words back to front
+                    // We use a signed comparisson here to allow dEnd to become
+                    // negative (happens when source and dest < 32). Valid
+                    // addresses in local memory will never be larger than
+                    // 2**255, so they can be safely re-interpreted as signed.
+                    // Note: the first check is always true,
+                    // this could have been a do-while loop.
+                    for {} slt(dest, dEnd) {} {
+                        mstore(dEnd, mload(sEnd))
+                        sEnd := sub(sEnd, 32)
+                        dEnd := sub(dEnd, 32)
+                    }
+                    
+                    // Write the first 32 bytes
+                    mstore(dest, first)
+                }
+            }
+        }
+    }
+    
+    /// @dev Returns a slices from a byte array.
+    /// @param b The byte array to take a slice from.
+    /// @param from The starting index for the slice (inclusive).
+    /// @param to The final index for the slice (exclusive).
+    /// @return result The slice containing bytes at indices [from, to)
+    function slice(bytes memory b, uint256 from, uint256 to)
+        internal
+        pure
+        returns (bytes memory result)
+    {
+        require(
+            from <= to,
+            "FROM_LESS_THAN_TO_REQUIRED"
+        );
+        require(
+            to < b.length,
+            "TO_LESS_THAN_LENGTH_REQUIRED"
+        );
+        
+        // Create a new bytes structure and copy contents
+        result = new bytes(to - from);
+        memCopy(
+            result.contentAddress(),
+            b.contentAddress() + from,
+            result.length);
+        return result;
+    }
+    
+    /// @dev Returns a slice from a byte array without preserving the input.
+    /// @param b The byte array to take a slice from. Will be destroyed in the process.
+    /// @param from The starting index for the slice (inclusive).
+    /// @param to The final index for the slice (exclusive).
+    /// @return result The slice containing bytes at indices [from, to)
+    /// @dev When `from == 0`, the original array will match the slice. In other cases its state will be corrupted.
+    function sliceDestructive(bytes memory b, uint256 from, uint256 to)
+        internal
+        pure
+        returns (bytes memory result)
+    {
+        require(
+            from <= to,
+            "FROM_LESS_THAN_TO_REQUIRED"
+        );
+        require(
+            to < b.length,
+            "TO_LESS_THAN_LENGTH_REQUIRED"
+        );
+        
+        // Create a new bytes structure around [from, to) in-place.
+        assembly {
+            result := add(b, from)
+            mstore(result, sub(to, from))
+        }
+        return result;
+    }
+
+    /// @dev Pops the last byte off of a byte array by modifying its length.
+    /// @param b Byte array that will be modified.
+    /// @return The byte that was popped off.
+    function popLastByte(bytes memory b)
+        internal
+        pure
+        returns (bytes1 result)
+    {
+        require(
+            b.length > 0,
+            "GREATER_THAN_ZERO_LENGTH_REQUIRED"
+        );
+
+        // Store last byte.
+        result = b[b.length - 1];
+
+        assembly {
+            // Decrement length of byte array.
+            let newLen := sub(mload(b), 1)
+            mstore(b, newLen)
+        }
+        return result;
+    }
+
+    /// @dev Pops the last 20 bytes off of a byte array by modifying its length.
+    /// @param b Byte array that will be modified.
+    /// @return The 20 byte address that was popped off.
+    function popLast20Bytes(bytes memory b)
+        internal
+        pure
+        returns (address result)
+    {
+        require(
+            b.length >= 20,
+            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
+        );
+
+        // Store last 20 bytes.
+        result = readAddress(b, b.length - 20);
+
+        assembly {
+            // Subtract 20 from byte array length.
+            let newLen := sub(mload(b), 20)
+            mstore(b, newLen)
+        }
+        return result;
+    }
+
+    /// @dev Tests equality of two byte arrays.
+    /// @param lhs First byte array to compare.
+    /// @param rhs Second byte array to compare.
+    /// @return True if arrays are the same. False otherwise.
+    function equals(
+        bytes memory lhs,
+        bytes memory rhs
+    )
+        internal
+        pure
+        returns (bool equal)
+    {
+        // Keccak gas cost is 30 + numWords * 6. This is a cheap way to compare.
+        // We early exit on unequal lengths, but keccak would also correctly
+        // handle this.
+        return lhs.length == rhs.length && keccak256(lhs) == keccak256(rhs);
+    }
+
+    /// @dev Reads an address from a position in a byte array.
+    /// @param b Byte array containing an address.
+    /// @param index Index in byte array of address.
+    /// @return address from byte array.
+    function readAddress(
+        bytes memory b,
+        uint256 index
+    )
+        internal
+        pure
+        returns (address result)
+    {
+        require(
+            b.length >= index + 20,  // 20 is length of address
+            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
+        );
+
+        // Add offset to index:
+        // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
+        // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
+        index += 20;
+
+        // Read address from array memory
+        assembly {
+            // 1. Add index to address of bytes array
+            // 2. Load 32-byte word from memory
+            // 3. Apply 20-byte mask to obtain address
+            result := and(mload(add(b, index)), 0xffffffffffffffffffffffffffffffffffffffff)
+        }
+        return result;
+    }
+
+    /// @dev Writes an address into a specific position in a byte array.
+    /// @param b Byte array to insert address into.
+    /// @param index Index in byte array of address.
+    /// @param input Address to put into byte array.
+    function writeAddress(
+        bytes memory b,
+        uint256 index,
+        address input
+    )
+        internal
+        pure
+    {
+        require(
+            b.length >= index + 20,  // 20 is length of address
+            "GREATER_OR_EQUAL_TO_20_LENGTH_REQUIRED"
+        );
+
+        // Add offset to index:
+        // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
+        // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
+        index += 20;
+
+        // Store address into array memory
+        assembly {
+            // The address occupies 20 bytes and mstore stores 32 bytes.
+            // First fetch the 32-byte word where we'll be storing the address, then
+            // apply a mask so we have only the bytes in the word that the address will not occupy.
+            // Then combine these bytes with the address and store the 32 bytes back to memory with mstore.
+
+            // 1. Add index to address of bytes array
+            // 2. Load 32-byte word from memory
+            // 3. Apply 12-byte mask to obtain extra bytes occupying word of memory where we'll store the address
+            let neighbors := and(mload(add(b, index)), 0xffffffffffffffffffffffff0000000000000000000000000000000000000000)
+            
+            // Make sure input address is clean.
+            // (Solidity does not guarantee this)
+            input := and(input, 0xffffffffffffffffffffffffffffffffffffffff)
+
+            // Store the neighbors and address into memory
+            mstore(add(b, index), xor(input, neighbors))
+        }
+    }
+
+    /// @dev Reads a bytes32 value from a position in a byte array.
+    /// @param b Byte array containing a bytes32 value.
+    /// @param index Index in byte array of bytes32 value.
+    /// @return bytes32 value from byte array.
+    function readBytes32(
+        bytes memory b,
+        uint256 index
+    )
+        internal
+        pure
+        returns (bytes32 result)
+    {
+        require(
+            b.length >= index + 32,
+            "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED"
+        );
+
+        // Arrays are prefixed by a 256 bit length parameter
+        index += 32;
+
+        // Read the bytes32 from array memory
+        assembly {
+            result := mload(add(b, index))
+        }
+        return result;
+    }
+
+    /// @dev Writes a bytes32 into a specific position in a byte array.
+    /// @param b Byte array to insert <input> into.
+    /// @param index Index in byte array of <input>.
+    /// @param input bytes32 to put into byte array.
+    function writeBytes32(
+        bytes memory b,
+        uint256 index,
+        bytes32 input
+    )
+        internal
+        pure
+    {
+        require(
+            b.length >= index + 32,
+            "GREATER_OR_EQUAL_TO_32_LENGTH_REQUIRED"
+        );
+
+        // Arrays are prefixed by a 256 bit length parameter
+        index += 32;
+
+        // Read the bytes32 from array memory
+        assembly {
+            mstore(add(b, index), input)
+        }
+    }
+
+    /// @dev Reads a uint256 value from a position in a byte array.
+    /// @param b Byte array containing a uint256 value.
+    /// @param index Index in byte array of uint256 value.
+    /// @return uint256 value from byte array.
+    function readUint256(
+        bytes memory b,
+        uint256 index
+    )
+        internal
+        pure
+        returns (uint256 result)
+    {
+        return uint256(readBytes32(b, index));
+    }
+
+    /// @dev Writes a uint256 into a specific position in a byte array.
+    /// @param b Byte array to insert <input> into.
+    /// @param index Index in byte array of <input>.
+    /// @param input uint256 to put into byte array.
+    function writeUint256(
+        bytes memory b,
+        uint256 index,
+        uint256 input
+    )
+        internal
+        pure
+    {
+        writeBytes32(b, index, bytes32(input));
+    }
+
+    /// @dev Reads an unpadded bytes4 value from a position in a byte array.
+    /// @param b Byte array containing a bytes4 value.
+    /// @param index Index in byte array of bytes4 value.
+    /// @return bytes4 value from byte array.
+    function readBytes4(
+        bytes memory b,
+        uint256 index)
+        internal
+        pure
+        returns (bytes4 result)
+    {
+        require(
+            b.length >= index + 4,
+            "GREATER_OR_EQUAL_TO_4_LENGTH_REQUIRED"
+        );
+        assembly {
+            result := mload(add(b, 32))
+            // Solidity does not require us to clean the trailing bytes.
+            // We do it anyway
+            result := and(result, 0xFFFFFFFF00000000000000000000000000000000000000000000000000000000)
+        }
+        return result;
+    }
+
+    /// @dev Reads nested bytes from a specific position.
+    /// @dev NOTE: the returned value overlaps with the input value.
+    ///            Both should be treated as immutable.
+    /// @param b Byte array containing nested bytes.
+    /// @param index Index of nested bytes.
+    /// @return result Nested bytes.
+    function readBytesWithLength(
+        bytes memory b,
+        uint256 index
+    )
+        internal
+        pure
+        returns (bytes memory result)
+    {
+        // Read length of nested bytes
+        uint256 nestedBytesLength = readUint256(b, index);
+        index += 32;
+
+        // Assert length of <b> is valid, given
+        // length of nested bytes
+        require(
+            b.length >= index + nestedBytesLength,
+            "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"
+        );
+        
+        // Return a pointer to the byte array as it exists inside `b`
+        assembly {
+            result := add(b, index)
+        }
+        return result;
+    }
+
+    /// @dev Inserts bytes at a specific position in a byte array.
+    /// @param b Byte array to insert <input> into.
+    /// @param index Index in byte array of <input>.
+    /// @param input bytes to insert.
+    function writeBytesWithLength(
+        bytes memory b,
+        uint256 index,
+        bytes memory input
+    )
+        internal
+        pure
+    {
+        // Assert length of <b> is valid, given
+        // length of input
+        require(
+            b.length >= index + 32 /* 32 bytes to store length */ + input.length,
+            "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"
+        );
+
+        // Copy <input> into <b>
+        memCopy(
+            b.contentAddress() + index,
+            input.rawAddress(), // includes length of <input>
+            input.length + 32   // +32 bytes to store <input> length
+        );
+    }
+
+    /// @dev Performs a deep copy of a byte array onto another byte array of greater than or equal length.
+    /// @param dest Byte array that will be overwritten with source bytes.
+    /// @param source Byte array to copy onto dest bytes.
+    function deepCopyBytes(
+        bytes memory dest,
+        bytes memory source
+    )
+        internal
+        pure
+    {
+        uint256 sourceLen = source.length;
+        // Dest length must be >= source length, or some bytes would not be copied.
+        require(
+            dest.length >= sourceLen,
+            "GREATER_OR_EQUAL_TO_SOURCE_BYTES_LENGTH_REQUIRED"
+        );
+        memCopy(
+            dest.contentAddress(),
+            source.contentAddress(),
+            sourceLen
+        );
+    }
+}
diff --git a/packages/contracts/src/2.0.0/utils/Ownable/IOwnable.sol b/packages/contracts/src/2.0.0/utils/Ownable/IOwnable.sol
new file mode 100644
index 000000000..e77680903
--- /dev/null
+++ b/packages/contracts/src/2.0.0/utils/Ownable/IOwnable.sol
@@ -0,0 +1,14 @@
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+/*
+ * Ownable
+ *
+ * Base contract with an owner.
+ * Provides onlyOwner modifier, which prevents function from running if it is called by anyone other than the owner.
+ */
+
+contract IOwnable {
+    function transferOwnership(address newOwner)
+        public;
+}
diff --git a/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol b/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol
new file mode 100644
index 000000000..6f5761cc7
--- /dev/null
+++ b/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol
@@ -0,0 +1,38 @@
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+/*
+ * Ownable
+ *
+ * Base contract with an owner.
+ * Provides onlyOwner modifier, which prevents function from running if it is called by anyone other than the owner.
+ */
+
+import "./IOwnable.sol";
+
+contract Ownable is IOwnable {
+    address public owner;
+
+    constructor ()
+        public
+    {
+        owner = msg.sender;
+    }
+
+    modifier onlyOwner() {
+        require(
+            msg.sender == owner,
+            "ONLY_CONTRACT_OWNER"
+        );
+        _;
+    }
+
+    function transferOwnership(address newOwner)
+        public
+        onlyOwner
+    {
+        if (newOwner != address(0)) {
+            owner = newOwner;
+        }
+    }
+}
diff --git a/packages/contracts/src/2.0.0/utils/SafeMath/SafeMath.sol b/packages/contracts/src/2.0.0/utils/SafeMath/SafeMath.sol
new file mode 100644
index 000000000..e137f6ca5
--- /dev/null
+++ b/packages/contracts/src/2.0.0/utils/SafeMath/SafeMath.sol
@@ -0,0 +1,74 @@
+pragma solidity ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+contract SafeMath {
+    function safeMul(uint a, uint b)
+        internal
+        pure
+        returns (uint256)
+    {
+        uint c = a * b;
+        assert(a == 0 || c / a == b);
+        return c;
+    }
+
+    function safeDiv(uint a, uint b)
+        internal
+        pure
+        returns (uint256)
+    {
+        uint c = a / b;
+        return c;
+    }
+
+    function safeSub(uint a, uint b)
+        internal
+        pure
+        returns (uint256)
+    {
+        assert(b <= a);
+        return a - b;
+    }
+
+    function safeAdd(uint a, uint b)
+        internal
+        pure
+        returns (uint256)
+    {
+        uint c = a + b;
+        assert(c >= a);
+        return c;
+    }
+
+    function max64(uint64 a, uint64 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        return a >= b ? a : b;
+    }
+
+    function min64(uint64 a, uint64 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        return a < b ? a : b;
+    }
+
+    function max256(uint256 a, uint256 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        return a >= b ? a : b;
+    }
+
+    function min256(uint256 a, uint256 b)
+        internal
+        pure
+        returns (uint256)
+    {
+        return a < b ? a : b;
+    }
+}