github.com/aigarnetwork/aigar@v0.0.0-20191115204914-d59a6eb70f8e/accounts/keystore/presale.go (about)

     1  //  Copyright 2018 The go-ethereum Authors
     2  //  Copyright 2019 The go-aigar Authors
     3  //  This file is part of the go-aigar library.
     4  //
     5  //  The go-aigar library is free software: you can redistribute it and/or modify
     6  //  it under the terms of the GNU Lesser General Public License as published by
     7  //  the Free Software Foundation, either version 3 of the License, or
     8  //  (at your option) any later version.
     9  //
    10  //  The go-aigar library is distributed in the hope that it will be useful,
    11  //  but WITHOUT ANY WARRANTY; without even the implied warranty of
    12  //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    13  //  GNU Lesser General Public License for more details.
    14  //
    15  //  You should have received a copy of the GNU Lesser General Public License
    16  //  along with the go-aigar library. If not, see <http://www.gnu.org/licenses/>.
    17  
    18  package keystore
    19  
    20  import (
    21  	"crypto/aes"
    22  	"crypto/cipher"
    23  	"crypto/sha256"
    24  	"encoding/hex"
    25  	"encoding/json"
    26  	"errors"
    27  	"fmt"
    28  
    29  	"github.com/AigarNetwork/aigar/accounts"
    30  	"github.com/AigarNetwork/aigar/crypto"
    31  	"github.com/pborman/uuid"
    32  	"golang.org/x/crypto/pbkdf2"
    33  )
    34  
    35  // creates a Key and stores that in the given KeyStore by decrypting a presale key JSON
    36  func importPreSaleKey(keyStore keyStore, keyJSON []byte, password string) (accounts.Account, *Key, error) {
    37  	key, err := decryptPreSaleKey(keyJSON, password)
    38  	if err != nil {
    39  		return accounts.Account{}, nil, err
    40  	}
    41  	key.Id = uuid.NewRandom()
    42  	a := accounts.Account{
    43  		Address: key.Address,
    44  		URL: accounts.URL{
    45  			Scheme: KeyStoreScheme,
    46  			Path:   keyStore.JoinPath(keyFileName(key.Address)),
    47  		},
    48  	}
    49  	err = keyStore.StoreKey(a.URL.Path, key, password)
    50  	return a, key, err
    51  }
    52  
    53  func decryptPreSaleKey(fileContent []byte, password string) (key *Key, err error) {
    54  	preSaleKeyStruct := struct {
    55  		EncSeed string
    56  		EthAddr string
    57  		Email   string
    58  		BtcAddr string
    59  	}{}
    60  	err = json.Unmarshal(fileContent, &preSaleKeyStruct)
    61  	if err != nil {
    62  		return nil, err
    63  	}
    64  	encSeedBytes, err := hex.DecodeString(preSaleKeyStruct.EncSeed)
    65  	if err != nil {
    66  		return nil, errors.New("invalid hex in encSeed")
    67  	}
    68  	if len(encSeedBytes) < 16 {
    69  		return nil, errors.New("invalid encSeed, too short")
    70  	}
    71  	iv := encSeedBytes[:16]
    72  	cipherText := encSeedBytes[16:]
    73  	/*
    74  		See https://github.com/ethereum/pyethsaletool
    75  
    76  		pyethsaletool generates the encryption key from password by
    77  		2000 rounds of PBKDF2 with HMAC-SHA-256 using password as salt (:().
    78  		16 byte key length within PBKDF2 and resulting key is used as AES key
    79  	*/
    80  	passBytes := []byte(password)
    81  	derivedKey := pbkdf2.Key(passBytes, passBytes, 2000, 16, sha256.New)
    82  	plainText, err := aesCBCDecrypt(derivedKey, cipherText, iv)
    83  	if err != nil {
    84  		return nil, err
    85  	}
    86  	ethPriv := crypto.Keccak256(plainText)
    87  	ecKey := crypto.ToECDSAUnsafe(ethPriv)
    88  
    89  	key = &Key{
    90  		Id:         nil,
    91  		Address:    crypto.PubkeyToAddress(ecKey.PublicKey),
    92  		PrivateKey: ecKey,
    93  	}
    94  	derivedAddr := hex.EncodeToString(key.Address.Bytes()) // needed because .Hex() gives leading "0x"
    95  	expectedAddr := preSaleKeyStruct.EthAddr
    96  	if derivedAddr != expectedAddr {
    97  		err = fmt.Errorf("decrypted addr '%s' not equal to expected addr '%s'", derivedAddr, expectedAddr)
    98  	}
    99  	return key, err
   100  }
   101  
   102  func aesCTRXOR(key, inText, iv []byte) ([]byte, error) {
   103  	// AES-128 is selected due to size of encryptKey.
   104  	aesBlock, err := aes.NewCipher(key)
   105  	if err != nil {
   106  		return nil, err
   107  	}
   108  	stream := cipher.NewCTR(aesBlock, iv)
   109  	outText := make([]byte, len(inText))
   110  	stream.XORKeyStream(outText, inText)
   111  	return outText, err
   112  }
   113  
   114  func aesCBCDecrypt(key, cipherText, iv []byte) ([]byte, error) {
   115  	aesBlock, err := aes.NewCipher(key)
   116  	if err != nil {
   117  		return nil, err
   118  	}
   119  	decrypter := cipher.NewCBCDecrypter(aesBlock, iv)
   120  	paddedPlaintext := make([]byte, len(cipherText))
   121  	decrypter.CryptBlocks(paddedPlaintext, cipherText)
   122  	plaintext := pkcs7Unpad(paddedPlaintext)
   123  	if plaintext == nil {
   124  		return nil, ErrDecrypt
   125  	}
   126  	return plaintext, err
   127  }
   128  
   129  // From https://leanpub.com/gocrypto/read#leanpub-auto-block-cipher-modes
   130  func pkcs7Unpad(in []byte) []byte {
   131  	if len(in) == 0 {
   132  		return nil
   133  	}
   134  
   135  	padding := in[len(in)-1]
   136  	if int(padding) > len(in) || padding > aes.BlockSize {
   137  		return nil
   138  	} else if padding == 0 {
   139  		return nil
   140  	}
   141  
   142  	for i := len(in) - 1; i > len(in)-int(padding)-1; i-- {
   143  		if in[i] != padding {
   144  			return nil
   145  		}
   146  	}
   147  	return in[:len(in)-int(padding)]
   148  }