github.com/arieschain/arieschain@v0.0.0-20191023063405-37c074544356/accounts/keystore/presale.go (about)

     1  package keystore
     2  
     3  import (
     4  	"crypto/aes"
     5  	"crypto/cipher"
     6  	"crypto/sha256"
     7  	"encoding/hex"
     8  	"encoding/json"
     9  	"errors"
    10  	"fmt"
    11  
    12  	"github.com/quickchainproject/quickchain/accounts"
    13  	"github.com/quickchainproject/quickchain/crypto"
    14  	"github.com/pborman/uuid"
    15  	"golang.org/x/crypto/pbkdf2"
    16  )
    17  
    18  // creates a Key and stores that in the given KeyStore by decrypting a presale key JSON
    19  func importPreSaleKey(keyStore keyStore, keyJSON []byte, password string) (accounts.Account, *Key, error) {
    20  	key, err := decryptPreSaleKey(keyJSON, password)
    21  	if err != nil {
    22  		return accounts.Account{}, nil, err
    23  	}
    24  	key.Id = uuid.NewRandom()
    25  	a := accounts.Account{Address: key.Address, URL: accounts.URL{Scheme: KeyStoreScheme, Path: keyStore.JoinPath(keyFileName(key.Address))}}
    26  	err = keyStore.StoreKey(a.URL.Path, key, password)
    27  	return a, key, err
    28  }
    29  
    30  func decryptPreSaleKey(fileContent []byte, password string) (key *Key, err error) {
    31  	preSaleKeyStruct := struct {
    32  		EncSeed string
    33  		EthAddr string
    34  		Email   string
    35  		BtcAddr string
    36  	}{}
    37  	err = json.Unmarshal(fileContent, &preSaleKeyStruct)
    38  	if err != nil {
    39  		return nil, err
    40  	}
    41  	encSeedBytes, err := hex.DecodeString(preSaleKeyStruct.EncSeed)
    42  	if err != nil {
    43  		return nil, errors.New("invalid hex in encSeed")
    44  	}
    45  	if len(encSeedBytes) < 16 {
    46  		return nil, errors.New("invalid encSeed, too short")
    47  	}
    48  	iv := encSeedBytes[:16]
    49  	cipherText := encSeedBytes[16:]
    50  	/*
    51  		See https://github.com/quickchain/pyethsaletool
    52  
    53  		pyethsaletool generates the encryption key from password by
    54  		2000 rounds of PBKDF2 with HMAC-SHA-256 using password as salt (:().
    55  		16 byte key length within PBKDF2 and resulting key is used as AES key
    56  	*/
    57  	passBytes := []byte(password)
    58  	derivedKey := pbkdf2.Key(passBytes, passBytes, 2000, 16, sha256.New)
    59  	plainText, err := aesCBCDecrypt(derivedKey, cipherText, iv)
    60  	if err != nil {
    61  		return nil, err
    62  	}
    63  	ethPriv := crypto.Keccak256(plainText)
    64  	ecKey := crypto.ToECDSAUnsafe(ethPriv)
    65  
    66  	key = &Key{
    67  		Id:         nil,
    68  		Address:    crypto.PubkeyToAddress(ecKey.PublicKey),
    69  		PrivateKey: ecKey,
    70  	}
    71  	derivedAddr := hex.EncodeToString(key.Address.Bytes()) // needed because .Hex() gives leading "0x"
    72  	expectedAddr := preSaleKeyStruct.EthAddr
    73  	if derivedAddr != expectedAddr {
    74  		err = fmt.Errorf("decrypted addr '%s' not equal to expected addr '%s'", derivedAddr, expectedAddr)
    75  	}
    76  	return key, err
    77  }
    78  
    79  func aesCTRXOR(key, inText, iv []byte) ([]byte, error) {
    80  	// AES-128 is selected due to size of encryptKey.
    81  	aesBlock, err := aes.NewCipher(key)
    82  	if err != nil {
    83  		return nil, err
    84  	}
    85  	stream := cipher.NewCTR(aesBlock, iv)
    86  	outText := make([]byte, len(inText))
    87  	stream.XORKeyStream(outText, inText)
    88  	return outText, err
    89  }
    90  
    91  func aesCBCDecrypt(key, cipherText, iv []byte) ([]byte, error) {
    92  	aesBlock, err := aes.NewCipher(key)
    93  	if err != nil {
    94  		return nil, err
    95  	}
    96  	decrypter := cipher.NewCBCDecrypter(aesBlock, iv)
    97  	paddedPlaintext := make([]byte, len(cipherText))
    98  	decrypter.CryptBlocks(paddedPlaintext, cipherText)
    99  	plaintext := pkcs7Unpad(paddedPlaintext)
   100  	if plaintext == nil {
   101  		return nil, ErrDecrypt
   102  	}
   103  	return plaintext, err
   104  }
   105  
   106  // From https://leanpub.com/gocrypto/read#leanpub-auto-block-cipher-modes
   107  func pkcs7Unpad(in []byte) []byte {
   108  	if len(in) == 0 {
   109  		return nil
   110  	}
   111  
   112  	padding := in[len(in)-1]
   113  	if int(padding) > len(in) || padding > aes.BlockSize {
   114  		return nil
   115  	} else if padding == 0 {
   116  		return nil
   117  	}
   118  
   119  	for i := len(in) - 1; i > len(in)-int(padding)-1; i-- {
   120  		if in[i] != padding {
   121  			return nil
   122  		}
   123  	}
   124  	return in[:len(in)-int(padding)]
   125  }