// Copyright 2014 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 crypto
import (
"crypto/aes"
"crypto/cipher"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/sha256"
"fmt"
"io"
"io/ioutil"
"math/big"
"os"
"encoding/hex"
"encoding/json"
"errors"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto/ecies"
"github.com/ethereum/go-ethereum/crypto/secp256k1"
"github.com/ethereum/go-ethereum/crypto/sha3"
"github.com/ethereum/go-ethereum/rlp"
"github.com/pborman/uuid"
"golang.org/x/crypto/pbkdf2"
"golang.org/x/crypto/ripemd160"
)
func Keccak256(data ...[]byte) []byte {
d := sha3.NewKeccak256()
for _, b := range data {
d.Write(b)
}
return d.Sum(nil)
}
func Keccak256Hash(data ...[]byte) (h common.Hash) {
d := sha3.NewKeccak256()
for _, b := range data {
d.Write(b)
}
d.Sum(h[:0])
return h
}
// Deprecated: For backward compatibility as other packages depend on these
func Sha3(data ...[]byte) []byte { return Keccak256(data...) }
func Sha3Hash(data ...[]byte) common.Hash { return Keccak256Hash(data...) }
// Creates an ethereum address given the bytes and the nonce
func CreateAddress(b common.Address, nonce uint64) common.Address {
data, _ := rlp.EncodeToBytes([]interface{}{b, nonce})
return common.BytesToAddress(Keccak256(data)[12:])
}
func Sha256(data []byte) []byte {
hash := sha256.Sum256(data)
return hash[:]
}
func Ripemd160(data []byte) []byte {
ripemd := ripemd160.New()
ripemd.Write(data)
return ripemd.Sum(nil)
}
func Ecrecover(hash, sig []byte) ([]byte, error) {
return secp256k1.RecoverPubkey(hash, sig)
}
// New methods using proper ecdsa keys from the stdlib
func ToECDSA(prv []byte) *ecdsa.PrivateKey {
if len(prv) == 0 {
return nil
}
priv := new(ecdsa.PrivateKey)
priv.PublicKey.Curve = secp256k1.S256()
priv.D = common.BigD(prv)
priv.PublicKey.X, priv.PublicKey.Y = secp256k1.S256().ScalarBaseMult(prv)
return priv
}
func FromECDSA(prv *ecdsa.PrivateKey) []byte {
if prv == nil {
return nil
}
return prv.D.Bytes()
}
func ToECDSAPub(pub []byte) *ecdsa.PublicKey {
if len(pub) == 0 {
return nil
}
x, y := elliptic.Unmarshal(secp256k1.S256(), pub)
return &ecdsa.PublicKey{secp256k1.S256(), x, y}
}
func FromECDSAPub(pub *ecdsa.PublicKey) []byte {
if pub == nil || pub.X == nil || pub.Y == nil {
return nil
}
return elliptic.Marshal(secp256k1.S256(), pub.X, pub.Y)
}
// HexToECDSA parses a secp256k1 private key.
func HexToECDSA(hexkey string) (*ecdsa.PrivateKey, error) {
b, err := hex.DecodeString(hexkey)
if err != nil {
return nil, errors.New("invalid hex string")
}
if len(b) != 32 {
return nil, errors.New("invalid length, need 256 bits")
}
return ToECDSA(b), nil
}
// LoadECDSA loads a secp256k1 private key from the given file.
// The key data is expected to be hex-encoded.
func LoadECDSA(file string) (*ecdsa.PrivateKey, error) {
buf := make([]byte, 64)
fd, err := os.Open(file)
if err != nil {
return nil, err
}
defer fd.Close()
if _, err := io.ReadFull(fd, buf); err != nil {
return nil, err
}
key, err := hex.DecodeString(string(buf))
if err != nil {
return nil, err
}
return ToECDSA(key), nil
}
// SaveECDSA saves a secp256k1 private key to the given file with
// restrictive permissions. The key data is saved hex-encoded.
func SaveECDSA(file string, key *ecdsa.PrivateKey) error {
k := hex.EncodeToString(FromECDSA(key))
return ioutil.WriteFile(file, []byte(k), 0600)
}
func GenerateKey() (*ecdsa.PrivateKey, error) {
return ecdsa.GenerateKey(secp256k1.S256(), rand.Reader)
}
func ValidateSignatureValues(v byte, r, s *big.Int, homestead bool) bool {
if r.Cmp(common.Big1) < 0 || s.Cmp(common.Big1) < 0 {
return false
}
vint := uint32(v)
// reject upper range of s values (ECDSA malleability)
// see discussion in secp256k1/libsecp256k1/include/secp256k1.h
if homestead && s.Cmp(secp256k1.HalfN) > 0 {
return false
}
// Frontier: allow s to be in full N range
if s.Cmp(secp256k1.N) >= 0 {
return false
}
if r.Cmp(secp256k1.N) < 0 && (vint == 27 || vint == 28) {
return true
} else {
return false
}
}
func SigToPub(hash, sig []byte) (*ecdsa.PublicKey, error) {
s, err := Ecrecover(hash, sig)
if err != nil {
return nil, err
}
x, y := elliptic.Unmarshal(secp256k1.S256(), s)
return &ecdsa.PublicKey{secp256k1.S256(), x, y}, nil
}
func Sign(hash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) {
if len(hash) != 32 {
return nil, fmt.Errorf("hash is required to be exactly 32 bytes (%d)", len(hash))
}
seckey := common.LeftPadBytes(prv.D.Bytes(), prv.Params().BitSize/8)
defer zeroBytes(seckey)
sig, err = secp256k1.Sign(hash, seckey)
return
}
func Encrypt(pub *ecdsa.PublicKey, message []byte) ([]byte, error) {
return ecies.Encrypt(rand.Reader, ecies.ImportECDSAPublic(pub), message, nil, nil)
}
func Decrypt(prv *ecdsa.PrivateKey, ct []byte) ([]byte, error) {
key := ecies.ImportECDSA(prv)
return key.Decrypt(rand.Reader, ct, nil, nil)
}
// Used only by block tests.
func ImportBlockTestKey(privKeyBytes []byte) error {
ks := NewKeyStorePassphrase(common.DefaultDataDir()+"/keystore", LightScryptN, LightScryptP)
ecKey := ToECDSA(privKeyBytes)
key := &Key{
Id: uuid.NewRandom(),
Address: PubkeyToAddress(ecKey.PublicKey),
PrivateKey: ecKey,
}
err := ks.StoreKey(key, "")
return err
}
// 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 := Keccak256(plainText)
ecKey := ToECDSA(ethPriv)
key = &Key{
Id: nil,
Address: 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
}
// AES-128 is selected due to size of encryptKey
func aesCTRXOR(key, inText, iv []byte) ([]byte, error) {
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)]
}
func PubkeyToAddress(p ecdsa.PublicKey) common.Address {
pubBytes := FromECDSAPub(&p)
return common.BytesToAddress(Keccak256(pubBytes[1:])[12:])
}
func zeroBytes(bytes []byte) {
for i := range bytes {
bytes[i] = 0
}
}
