139 lines
4.1 KiB
Go
139 lines
4.1 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package keystore
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/sha256"
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"encoding/hex"
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"encoding/json"
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"errors"
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"fmt"
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"github.com/ethereum/go-ethereum/accounts"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/pborman/uuid"
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"golang.org/x/crypto/pbkdf2"
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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 keyStore, keyJSON []byte, password string) (accounts.Account, *Key, error) {
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key, err := decryptPreSaleKey(keyJSON, password)
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if err != nil {
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return accounts.Account{}, nil, err
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}
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key.Id = uuid.NewRandom()
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a := accounts.Account{Address: key.Address, URL: accounts.URL{Scheme: KeyStoreScheme, Path: keyStore.JoinPath(keyFileName(key.Address))}}
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err = keyStore.StoreKey(a.URL.Path, key, password)
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return a, 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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if err != nil {
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return nil, errors.New("invalid hex in encSeed")
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}
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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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if err != nil {
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return nil, err
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}
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ethPriv := crypto.Keccak256(plainText)
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ecKey := crypto.ToECDSAUnsafe(ethPriv)
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key = &Key{
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Id: nil,
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Address: crypto.PubkeyToAddress(ecKey.PublicKey),
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PrivateKey: ecKey,
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}
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derivedAddr := hex.EncodeToString(key.Address.Bytes()) // needed because .Hex() gives leading "0x"
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expectedAddr := preSaleKeyStruct.EthAddr
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if derivedAddr != expectedAddr {
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err = fmt.Errorf("decrypted addr '%s' not equal to expected addr '%s'", derivedAddr, expectedAddr)
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}
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return key, err
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}
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func aesCTRXOR(key, inText, iv []byte) ([]byte, error) {
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// AES-128 is selected due to size of encryptKey.
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aesBlock, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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stream := cipher.NewCTR(aesBlock, iv)
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outText := make([]byte, len(inText))
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stream.XORKeyStream(outText, inText)
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return outText, err
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}
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func aesCBCDecrypt(key, cipherText, iv []byte) ([]byte, error) {
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aesBlock, err := aes.NewCipher(key)
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if err != nil {
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return nil, 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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return nil, ErrDecrypt
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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 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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