1 files changed, 132 insertions, 0 deletions
diff --git a/accounts/presale.go b/accounts/presale.go
new file mode 100644
index 000000000..8faa98558
--- /dev/null
+++ b/accounts/presale.go
@@ -0,0 +1,132 @@
+// Copyright 2016 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 (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/pborman/uuid"
+	"golang.org/x/crypto/pbkdf2"
+)
+
+// creates a Key and stores that in the given KeyStore by decrypting a presale key JSON
+func importPreSaleKey(keyStore keyStore, keyJSON []byte, password string) (*Key, error) {
+	key, err := decryptPreSaleKey(keyJSON, password)
+	if err != nil {
+		return nil, err
+	}
+	key.Id = uuid.NewRandom()
+	err = keyStore.StoreKey(key, password)
+	return key, err
+}
+
+func decryptPreSaleKey(fileContent []byte, password string) (key *Key, err error) {
+	preSaleKeyStruct := struct {
+		EncSeed string
+		EthAddr string
+		Email   string
+		BtcAddr string
+	}{}
+	err = json.Unmarshal(fileContent, &preSaleKeyStruct)
+	if err != nil {
+		return nil, err
+	}
+	encSeedBytes, err := hex.DecodeString(preSaleKeyStruct.EncSeed)
+	iv := encSeedBytes[:16]
+	cipherText := encSeedBytes[16:]
+	/*
+		See https://github.com/ethereum/pyethsaletool
+
+		pyethsaletool generates the encryption key from password by
+		2000 rounds of PBKDF2 with HMAC-SHA-256 using password as salt (:().
+		16 byte key length within PBKDF2 and resulting key is used as AES key
+	*/
+	passBytes := []byte(password)
+	derivedKey := pbkdf2.Key(passBytes, passBytes, 2000, 16, sha256.New)
+	plainText, err := aesCBCDecrypt(derivedKey, cipherText, iv)
+	if err != nil {
+		return nil, err
+	}
+	ethPriv := crypto.Keccak256(plainText)
+	ecKey := crypto.ToECDSA(ethPriv)
+	key = &Key{
+		Id:         nil,
+		Address:    crypto.PubkeyToAddress(ecKey.PublicKey),
+		PrivateKey: ecKey,
+	}
+	derivedAddr := hex.EncodeToString(key.Address.Bytes()) // needed because .Hex() gives leading "0x"
+	expectedAddr := preSaleKeyStruct.EthAddr
+	if derivedAddr != expectedAddr {
+		err = fmt.Errorf("decrypted addr '%s' not equal to expected addr '%s'", derivedAddr, expectedAddr)
+	}
+	return key, err
+}
+
+func aesCTRXOR(key, inText, iv []byte) ([]byte, error) {
+	// AES-128 is selected due to size of encryptKey.
+	aesBlock, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	stream := cipher.NewCTR(aesBlock, iv)
+	outText := make([]byte, len(inText))
+	stream.XORKeyStream(outText, inText)
+	return outText, err
+}
+
+func aesCBCDecrypt(key, cipherText, iv []byte) ([]byte, error) {
+	aesBlock, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	decrypter := cipher.NewCBCDecrypter(aesBlock, iv)
+	paddedPlaintext := make([]byte, len(cipherText))
+	decrypter.CryptBlocks(paddedPlaintext, cipherText)
+	plaintext := pkcs7Unpad(paddedPlaintext)
+	if plaintext == nil {
+		err = errors.New("Decryption failed: PKCS7Unpad failed after AES decryption")
+	}
+	return plaintext, err
+}
+
+// From https://leanpub.com/gocrypto/read#leanpub-auto-block-cipher-modes
+func pkcs7Unpad(in []byte) []byte {
+	if len(in) == 0 {
+		return nil
+	}
+
+	padding := in[len(in)-1]
+	if int(padding) > len(in) || padding > aes.BlockSize {
+		return nil
+	} else if padding == 0 {
+		return nil
+	}
+
+	for i := len(in) - 1; i > len(in)-int(padding)-1; i-- {
+		if in[i] != padding {
+			return nil
+		}
+	}
+	return in[:len(in)-int(padding)]
+}