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authorPéter Szilágyi <peterke@gmail.com>2017-02-09 02:25:52 +0800
committerPéter Szilágyi <peterke@gmail.com>2017-02-13 20:00:09 +0800
commit205ea9580215cca4093dff22ec61222bc3a6ff96 (patch)
treeaf6c38683d64bb47c0a31ba166533701cf95ed15 /accounts/hd.go
parentc5215fdd48231622dd56aba63a5187c6e42828d4 (diff)
downloaddexon-205ea9580215cca4093dff22ec61222bc3a6ff96.tar.gz
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accounts, cmd, internal, node: implement HD wallet self-derivation
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-rw-r--r--accounts/hd.go130
1 files changed, 130 insertions, 0 deletions
diff --git a/accounts/hd.go b/accounts/hd.go
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+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library 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 Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package accounts
+
+import (
+ "errors"
+ "fmt"
+ "math"
+ "math/big"
+ "strings"
+)
+
+// DefaultRootDerivationPath is the root path to which custom derivation endpoints
+// are appended. As such, the first account will be at m/44'/60'/0'/0, the second
+// at m/44'/60'/0'/1, etc.
+var DefaultRootDerivationPath = DerivationPath{0x80000000 + 44, 0x80000000 + 60, 0x80000000 + 0}
+
+// DefaultBaseDerivationPath is the base path from which custom derivation endpoints
+// are incremented. As such, the first account will be at m/44'/60'/0'/0, the second
+// at m/44'/60'/0'/1, etc.
+var DefaultBaseDerivationPath = DerivationPath{0x80000000 + 44, 0x80000000 + 60, 0x80000000 + 0, 0}
+
+// DerivationPath represents the computer friendly version of a hierarchical
+// deterministic wallet account derivaion path.
+//
+// The BIP-32 spec https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki
+// defines derivation paths to be of the form:
+//
+// m / purpose' / coin_type' / account' / change / address_index
+//
+// The BIP-44 spec https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki
+// defines that the `purpose` be 44' (or 0x8000002C) for crypto currencies, and
+// SLIP-44 https://github.com/satoshilabs/slips/blob/master/slip-0044.md assigns
+// the `coin_type` 60' (or 0x8000003C) to Ethereum.
+//
+// The root path for Ethereum is m/44'/60'/0'/0 according to the specification
+// from https://github.com/ethereum/EIPs/issues/84, albeit it's not set in stone
+// yet whether accounts should increment the last component or the children of
+// that. We will go with the simpler approach of incrementing the last component.
+type DerivationPath []uint32
+
+// ParseDerivationPath converts a user specified derivation path string to the
+// internal binary representation.
+//
+// Full derivation paths need to start with the `m/` prefix, relative derivation
+// paths (which will get appended to the default root path) must not have prefixes
+// in front of the first element. Whitespace is ignored.
+func ParseDerivationPath(path string) (DerivationPath, error) {
+ var result DerivationPath
+
+ // Handle absolute or relative paths
+ components := strings.Split(path, "/")
+ switch {
+ case len(components) == 0:
+ return nil, errors.New("empty derivation path")
+
+ case strings.TrimSpace(components[0]) == "":
+ return nil, errors.New("ambiguous path: use 'm/' prefix for absolute paths, or no leading '/' for relative ones")
+
+ case strings.TrimSpace(components[0]) == "m":
+ components = components[1:]
+
+ default:
+ result = append(result, DefaultRootDerivationPath...)
+ }
+ // All remaining components are relative, append one by one
+ if len(components) == 0 {
+ return nil, errors.New("empty derivation path") // Empty relative paths
+ }
+ for _, component := range components {
+ // Ignore any user added whitespace
+ component = strings.TrimSpace(component)
+ var value uint32
+
+ // Handle hardened paths
+ if strings.HasSuffix(component, "'") {
+ value = 0x80000000
+ component = strings.TrimSpace(strings.TrimSuffix(component, "'"))
+ }
+ // Handle the non hardened component
+ bigval, ok := new(big.Int).SetString(component, 0)
+ if !ok {
+ return nil, fmt.Errorf("invalid component: %s", component)
+ }
+ max := math.MaxUint32 - value
+ if bigval.Sign() < 0 || bigval.Cmp(big.NewInt(int64(max))) > 0 {
+ if value == 0 {
+ return nil, fmt.Errorf("component %v out of allowed range [0, %d]", bigval, max)
+ }
+ return nil, fmt.Errorf("component %v out of allowed hardened range [0, %d]", bigval, max)
+ }
+ value += uint32(bigval.Uint64())
+
+ // Append and repeat
+ result = append(result, value)
+ }
+ return result, nil
+}
+
+// String implements the stringer interface, converting a binary derivation path
+// to its canonical representation.
+func (path DerivationPath) String() string {
+ result := "m"
+ for _, component := range path {
+ var hardened bool
+ if component >= 0x80000000 {
+ component -= 0x80000000
+ hardened = true
+ }
+ result = fmt.Sprintf("%s/%d", result, component)
+ if hardened {
+ result += "'"
+ }
+ }
+ return result
+}