272 lines
6.4 KiB
Go
272 lines
6.4 KiB
Go
package crypto
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/ecdsa"
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"crypto/elliptic"
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"crypto/rand"
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"crypto/sha256"
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"fmt"
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"io"
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"os"
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"encoding/hex"
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"encoding/json"
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"errors"
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"code.google.com/p/go-uuid/uuid"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/crypto/ecies"
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"github.com/ethereum/go-ethereum/crypto/secp256k1"
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"github.com/ethereum/go-ethereum/crypto/sha3"
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"github.com/ethereum/go-ethereum/rlp"
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"golang.org/x/crypto/pbkdf2"
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"golang.org/x/crypto/ripemd160"
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)
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func init() {
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// specify the params for the s256 curve
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ecies.AddParamsForCurve(S256(), ecies.ECIES_AES128_SHA256)
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}
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func Sha3(data ...[]byte) []byte {
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d := sha3.NewKeccak256()
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for _, b := range data {
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d.Write(b)
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}
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return d.Sum(nil)
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}
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func Sha3Hash(data ...[]byte) (h common.Hash) {
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d := sha3.NewKeccak256()
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for _, b := range data {
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d.Write(b)
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}
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d.Sum(h[:0])
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return h
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}
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// Creates an ethereum address given the bytes and the nonce
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func CreateAddress(b common.Address, nonce uint64) common.Address {
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data, _ := rlp.EncodeToBytes([]interface{}{b, nonce})
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return common.BytesToAddress(Sha3(data)[12:])
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//return Sha3(common.NewValue([]interface{}{b, nonce}).Encode())[12:]
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}
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func Sha256(data []byte) []byte {
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hash := sha256.Sum256(data)
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return hash[:]
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}
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func Ripemd160(data []byte) []byte {
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ripemd := ripemd160.New()
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ripemd.Write(data)
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return ripemd.Sum(nil)
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}
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func Ecrecover(data []byte) []byte {
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var in = struct {
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hash []byte
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sig []byte
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}{data[:32], data[32:]}
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r, _ := secp256k1.RecoverPubkey(in.hash, in.sig)
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return r
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}
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// New methods using proper ecdsa keys from the stdlib
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func ToECDSA(prv []byte) *ecdsa.PrivateKey {
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if len(prv) == 0 {
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return nil
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}
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priv := new(ecdsa.PrivateKey)
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priv.PublicKey.Curve = S256()
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priv.D = common.BigD(prv)
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priv.PublicKey.X, priv.PublicKey.Y = S256().ScalarBaseMult(prv)
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return priv
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}
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func FromECDSA(prv *ecdsa.PrivateKey) []byte {
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if prv == nil {
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return nil
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}
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return prv.D.Bytes()
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}
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func ToECDSAPub(pub []byte) *ecdsa.PublicKey {
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if len(pub) == 0 {
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return nil
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}
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x, y := elliptic.Unmarshal(S256(), pub)
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return &ecdsa.PublicKey{S256(), x, y}
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}
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func FromECDSAPub(pub *ecdsa.PublicKey) []byte {
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if pub == nil || pub.X == nil || pub.Y == nil {
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return nil
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}
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return elliptic.Marshal(S256(), pub.X, pub.Y)
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}
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// HexToECDSA parses a secp256k1 private key.
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func HexToECDSA(hexkey string) (*ecdsa.PrivateKey, error) {
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b, err := hex.DecodeString(hexkey)
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if err != nil {
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return nil, errors.New("invalid hex string")
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}
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if len(b) != 32 {
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return nil, errors.New("invalid length, need 256 bits")
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}
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return ToECDSA(b), nil
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}
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// LoadECDSA loads a secp256k1 private key from the given file.
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func LoadECDSA(file string) (*ecdsa.PrivateKey, error) {
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buf := make([]byte, 32)
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fd, err := os.Open(file)
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if err != nil {
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return nil, err
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}
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defer fd.Close()
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if _, err := io.ReadFull(fd, buf); err != nil {
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return nil, err
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}
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return ToECDSA(buf), nil
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}
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func GenerateKey() (*ecdsa.PrivateKey, error) {
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return ecdsa.GenerateKey(S256(), rand.Reader)
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}
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func SigToPub(hash, sig []byte) *ecdsa.PublicKey {
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s := Ecrecover(append(hash, sig...))
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x, y := elliptic.Unmarshal(S256(), s)
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return &ecdsa.PublicKey{S256(), x, y}
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}
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func Sign(hash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) {
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if len(hash) != 32 {
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return nil, fmt.Errorf("hash is required to be exactly 32 bytes (%d)", len(hash))
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}
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sig, err = secp256k1.Sign(hash, common.LeftPadBytes(prv.D.Bytes(), prv.Params().BitSize/8))
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return
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}
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func Encrypt(pub *ecdsa.PublicKey, message []byte) ([]byte, error) {
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return ecies.Encrypt(rand.Reader, ecies.ImportECDSAPublic(pub), message, nil, nil)
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}
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func Decrypt(prv *ecdsa.PrivateKey, ct []byte) ([]byte, error) {
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key := ecies.ImportECDSA(prv)
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return key.Decrypt(rand.Reader, ct, nil, nil)
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}
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// creates a Key and stores that in the given KeyStore by decrypting a presale key JSON
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func ImportPreSaleKey(keyStore KeyStore2, keyJSON []byte, password string) (*Key, error) {
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key, err := decryptPreSaleKey(keyJSON, password)
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if err != nil {
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return nil, err
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}
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key.Id = uuid.NewRandom()
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err = keyStore.StoreKey(key, password)
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return key, err
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}
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func decryptPreSaleKey(fileContent []byte, password string) (key *Key, err error) {
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preSaleKeyStruct := struct {
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EncSeed string
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EthAddr string
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Email string
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BtcAddr string
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}{}
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err = json.Unmarshal(fileContent, &preSaleKeyStruct)
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if err != nil {
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return nil, err
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}
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encSeedBytes, err := hex.DecodeString(preSaleKeyStruct.EncSeed)
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iv := encSeedBytes[:16]
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cipherText := encSeedBytes[16:]
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/*
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See https://github.com/ethereum/pyethsaletool
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pyethsaletool generates the encryption key from password by
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2000 rounds of PBKDF2 with HMAC-SHA-256 using password as salt (:().
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16 byte key length within PBKDF2 and resulting key is used as AES key
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*/
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passBytes := []byte(password)
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derivedKey := pbkdf2.Key(passBytes, passBytes, 2000, 16, sha256.New)
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plainText, err := aesCBCDecrypt(derivedKey, cipherText, iv)
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ethPriv := Sha3(plainText)
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ecKey := ToECDSA(ethPriv)
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key = &Key{
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Id: nil,
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Address: PubkeyToAddress(ecKey.PublicKey),
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PrivateKey: ecKey,
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}
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derivedAddr := common.Bytes2Hex(key.Address)
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expectedAddr := preSaleKeyStruct.EthAddr
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if derivedAddr != expectedAddr {
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err = errors.New("decrypted addr not equal to expected addr")
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}
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return key, err
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}
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func aesCBCDecrypt(key []byte, cipherText []byte, iv []byte) (plainText []byte, err error) {
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aesBlock, err := aes.NewCipher(key)
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if err != nil {
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return plainText, err
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}
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decrypter := cipher.NewCBCDecrypter(aesBlock, iv)
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paddedPlainText := make([]byte, len(cipherText))
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decrypter.CryptBlocks(paddedPlainText, cipherText)
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plainText = PKCS7Unpad(paddedPlainText)
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if plainText == nil {
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err = errors.New("Decryption failed: PKCS7Unpad failed after decryption")
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}
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return plainText, err
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}
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// From https://leanpub.com/gocrypto/read#leanpub-auto-block-cipher-modes
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func PKCS7Pad(in []byte) []byte {
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padding := 16 - (len(in) % 16)
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if padding == 0 {
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padding = 16
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}
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for i := 0; i < padding; i++ {
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in = append(in, byte(padding))
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}
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return in
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}
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func PKCS7Unpad(in []byte) []byte {
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if len(in) == 0 {
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return nil
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}
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padding := in[len(in)-1]
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if int(padding) > len(in) || padding > aes.BlockSize {
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return nil
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} else if padding == 0 {
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return nil
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}
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for i := len(in) - 1; i > len(in)-int(padding)-1; i-- {
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if in[i] != padding {
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return nil
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}
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}
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return in[:len(in)-int(padding)]
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}
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func PubkeyToAddress(p ecdsa.PublicKey) []byte {
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pubBytes := FromECDSAPub(&p)
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return Sha3(pubBytes[1:])[12:]
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}
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