package crypto import ( "crypto/aes" "crypto/cipher" "crypto/ecdsa" "crypto/elliptic" "crypto/rand" "crypto/sha256" "fmt" "encoding/hex" "encoding/json" "errors" "code.google.com/p/go-uuid/uuid" "code.google.com/p/go.crypto/pbkdf2" "code.google.com/p/go.crypto/ripemd160" "github.com/ethereum/go-ethereum/crypto/secp256k1" "github.com/ethereum/go-ethereum/crypto/sha3" "github.com/ethereum/go-ethereum/ethutil" "github.com/obscuren/ecies" ) func init() { // specify the params for the s256 curve ecies.AddParamsForCurve(S256(), ecies.ECIES_AES128_SHA256) } func Sha3(data []byte) []byte { d := sha3.NewKeccak256() d.Write(data) return d.Sum(nil) } // Creates an ethereum address given the bytes and the nonce func CreateAddress(b []byte, nonce uint64) []byte { return Sha3(ethutil.NewValue([]interface{}{b, nonce}).Encode())[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(data []byte) []byte { var in = struct { hash []byte sig []byte }{data[:32], data[32:]} r, _ := secp256k1.RecoverPubkey(in.hash, in.sig) return r } // 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 = S256() priv.D = ethutil.BigD(prv) priv.PublicKey.X, priv.PublicKey.Y = 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(S256(), pub) return &ecdsa.PublicKey{S256(), x, y} } func FromECDSAPub(pub *ecdsa.PublicKey) []byte { if pub == nil { return nil } return elliptic.Marshal(S256(), pub.X, pub.Y) } func GenerateKey() (*ecdsa.PrivateKey, error) { return ecdsa.GenerateKey(S256(), rand.Reader) } func SigToPub(hash, sig []byte) *ecdsa.PublicKey { s := Ecrecover(append(hash, sig...)) x, y := elliptic.Unmarshal(S256(), s) return &ecdsa.PublicKey{S256(), x, y} } 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)) } sig, err = secp256k1.Sign(hash, ethutil.LeftPadBytes(prv.D.Bytes(), prv.Params().BitSize/8)) 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) } // creates a Key and stores that in the given KeyStore by decrypting a presale key JSON func ImportPreSaleKey(keyStore KeyStore2, 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) ethPriv := Sha3(plainText) ecKey := ToECDSA(ethPriv) key = &Key{ Id: nil, Address: PubkeyToAddress(ecKey.PublicKey), PrivateKey: ecKey, } derivedAddr := ethutil.Bytes2Hex(key.Address) expectedAddr := preSaleKeyStruct.EthAddr if derivedAddr != expectedAddr { err = errors.New("decrypted addr not equal to expected addr") } return key, err } func aesCBCDecrypt(key []byte, cipherText []byte, iv []byte) (plainText []byte, err error) { aesBlock, err := aes.NewCipher(key) if err != nil { return plainText, 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 decryption") } return plainText, err } // From https://leanpub.com/gocrypto/read#leanpub-auto-block-cipher-modes func PKCS7Pad(in []byte) []byte { padding := 16 - (len(in) % 16) if padding == 0 { padding = 16 } for i := 0; i < padding; i++ { in = append(in, byte(padding)) } return in } 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) []byte { pubBytes := FromECDSAPub(&p) return Sha3(pubBytes[1:])[12:] }