github.com/halybang/go-ethereum@v1.0.5-0.20180325041310-3b262bc1367c/accounts/keystore/presale.go (about)

     1  // Copyright 2016 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package keystore
    18  
    19  import (
    20  	"crypto/aes"
    21  	"crypto/cipher"
    22  	"crypto/sha256"
    23  	"encoding/hex"
    24  	"encoding/json"
    25  	"errors"
    26  	"fmt"
    27  
    28  	"github.com/pborman/uuid"
    29  	"github.com/wanchain/go-wanchain/accounts"
    30  	"github.com/wanchain/go-wanchain/crypto"
    31  	"golang.org/x/crypto/pbkdf2"
    32  )
    33  
    34  // creates a Key and stores that in the given KeyStore by decrypting a presale key JSON
    35  func importPreSaleKey(keyStore keyStore, keyJSON []byte, password string) (accounts.Account, *Key, error) {
    36  	key, err := decryptPreSaleKey(keyJSON, password)
    37  	if err != nil {
    38  		return accounts.Account{}, nil, err
    39  	}
    40  	key.Id = uuid.NewRandom()
    41  
    42  	// add a second sk field for wanchain address
    43  	sk, err := crypto.GenerateKey()
    44  	if err != nil {
    45  		return accounts.Account{}, nil, err
    46  	}
    47  	key.PrivateKey2 = sk
    48  
    49  	a := accounts.Account{Address: key.Address, URL: accounts.URL{Scheme: KeyStoreScheme, Path: keyStore.JoinPath(keyFileName(key.Address))}}
    50  	err = keyStore.StoreKey(a.URL.Path, key, password)
    51  	return a, key, err
    52  }
    53  
    54  func decryptPreSaleKey(fileContent []byte, password string) (key *Key, err error) {
    55  	preSaleKeyStruct := struct {
    56  		EncSeed string
    57  		EthAddr string
    58  		Email   string
    59  		BtcAddr string
    60  	}{}
    61  	err = json.Unmarshal(fileContent, &preSaleKeyStruct)
    62  	if err != nil {
    63  		return nil, err
    64  	}
    65  	encSeedBytes, err := hex.DecodeString(preSaleKeyStruct.EncSeed)
    66  	if err != nil {
    67  		return nil, errors.New("invalid hex in encSeed")
    68  	}
    69  	iv := encSeedBytes[:16]
    70  	cipherText := encSeedBytes[16:]
    71  	/*
    72  		See https://github.com/ethereum/pyethsaletool
    73  
    74  		pyethsaletool generates the encryption key from password by
    75  		2000 rounds of PBKDF2 with HMAC-SHA-256 using password as salt (:().
    76  		16 byte key length within PBKDF2 and resulting key is used as AES key
    77  	*/
    78  	passBytes := []byte(password)
    79  	derivedKey := pbkdf2.Key(passBytes, passBytes, 2000, 16, sha256.New)
    80  	plainText, err := aesCBCDecrypt(derivedKey, cipherText, iv)
    81  	if err != nil {
    82  		return nil, err
    83  	}
    84  	ethPriv := crypto.Keccak256(plainText)
    85  	ecKey := crypto.ToECDSAUnsafe(ethPriv)
    86  
    87  	key = &Key{
    88  		Id:         nil,
    89  		Address:    crypto.PubkeyToAddress(ecKey.PublicKey),
    90  		PrivateKey: ecKey,
    91  	}
    92  	derivedAddr := hex.EncodeToString(key.Address.Bytes()) // needed because .Hex() gives leading "0x"
    93  	expectedAddr := preSaleKeyStruct.EthAddr
    94  	if derivedAddr != expectedAddr {
    95  		err = fmt.Errorf("decrypted addr '%s' not equal to expected addr '%s'", derivedAddr, expectedAddr)
    96  	}
    97  	return key, err
    98  }
    99  
   100  func aesCTRXOR(key, inText, iv []byte) ([]byte, error) {
   101  	// AES-128 is selected due to size of encryptKey.
   102  	aesBlock, err := aes.NewCipher(key)
   103  	if err != nil {
   104  		return nil, err
   105  	}
   106  	stream := cipher.NewCTR(aesBlock, iv)
   107  	outText := make([]byte, len(inText))
   108  	stream.XORKeyStream(outText, inText)
   109  	return outText, err
   110  }
   111  
   112  func aesCBCDecrypt(key, cipherText, iv []byte) ([]byte, error) {
   113  	aesBlock, err := aes.NewCipher(key)
   114  	if err != nil {
   115  		return nil, err
   116  	}
   117  	decrypter := cipher.NewCBCDecrypter(aesBlock, iv)
   118  	paddedPlaintext := make([]byte, len(cipherText))
   119  	decrypter.CryptBlocks(paddedPlaintext, cipherText)
   120  	plaintext := pkcs7Unpad(paddedPlaintext)
   121  	if plaintext == nil {
   122  		return nil, ErrDecrypt
   123  	}
   124  	return plaintext, err
   125  }
   126  
   127  // From https://leanpub.com/gocrypto/read#leanpub-auto-block-cipher-modes
   128  func pkcs7Unpad(in []byte) []byte {
   129  	if len(in) == 0 {
   130  		return nil
   131  	}
   132  
   133  	padding := in[len(in)-1]
   134  	if int(padding) > len(in) || padding > aes.BlockSize {
   135  		return nil
   136  	} else if padding == 0 {
   137  		return nil
   138  	}
   139  
   140  	for i := len(in) - 1; i > len(in)-int(padding)-1; i-- {
   141  		if in[i] != padding {
   142  			return nil
   143  		}
   144  	}
   145  	return in[:len(in)-int(padding)]
   146  }