a9f26dcd0d
In order to avoid disk thrashing for Accounts and HasAccount, address->key file mappings are now cached in memory. This makes it no longer necessary to keep the key address in the file name. The address of each key is derived from file content instead. There are minor user-visible changes: - "geth account list" now reports key file paths alongside the address. - If multiple keys are present for an address, unlocking by address is not possible. Users are directed to remove the duplicate files instead. Unlocking by index is still possible. - Key files are overwritten written in place when updating the password.
298 lines
8.2 KiB
Go
298 lines
8.2 KiB
Go
// Copyright 2014 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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/*
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This key store behaves as KeyStorePlain with the difference that
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the private key is encrypted and on disk uses another JSON encoding.
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The crypto is documented at https://github.com/ethereum/wiki/wiki/Web3-Secret-Storage-Definition
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*/
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package accounts
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import (
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"bytes"
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"crypto/aes"
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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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"io/ioutil"
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"path/filepath"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/crypto/randentropy"
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"github.com/pborman/uuid"
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"golang.org/x/crypto/pbkdf2"
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"golang.org/x/crypto/scrypt"
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)
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const (
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keyHeaderKDF = "scrypt"
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// n,r,p = 2^18, 8, 1 uses 256MB memory and approx 1s CPU time on a modern CPU.
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StandardScryptN = 1 << 18
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StandardScryptP = 1
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// n,r,p = 2^12, 8, 6 uses 4MB memory and approx 100ms CPU time on a modern CPU.
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LightScryptN = 1 << 12
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LightScryptP = 6
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scryptR = 8
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scryptDKLen = 32
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)
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type keyStorePassphrase struct {
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keysDirPath string
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scryptN int
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scryptP int
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}
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func (ks keyStorePassphrase) GetKey(addr common.Address, filename, auth string) (*Key, error) {
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// Load the key from the keystore and decrypt its contents
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keyjson, err := ioutil.ReadFile(filename)
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if err != nil {
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return nil, err
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}
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key, err := DecryptKey(keyjson, auth)
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if err != nil {
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return nil, err
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}
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// Make sure we're really operating on the requested key (no swap attacks)
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if key.Address != addr {
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return nil, fmt.Errorf("key content mismatch: have account %x, want %x", key.Address, addr)
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}
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return key, nil
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}
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func (ks keyStorePassphrase) StoreKey(filename string, key *Key, auth string) error {
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keyjson, err := EncryptKey(key, auth, ks.scryptN, ks.scryptP)
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if err != nil {
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return err
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}
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return writeKeyFile(filename, keyjson)
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}
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func (ks keyStorePassphrase) JoinPath(filename string) string {
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if filepath.IsAbs(filename) {
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return filename
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} else {
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return filepath.Join(ks.keysDirPath, filename)
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}
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}
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// EncryptKey encrypts a key using the specified scrypt parameters into a json
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// blob that can be decrypted later on.
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func EncryptKey(key *Key, auth string, scryptN, scryptP int) ([]byte, error) {
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authArray := []byte(auth)
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salt := randentropy.GetEntropyCSPRNG(32)
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derivedKey, err := scrypt.Key(authArray, salt, scryptN, scryptR, scryptP, scryptDKLen)
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if err != nil {
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return nil, err
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}
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encryptKey := derivedKey[:16]
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keyBytes := crypto.FromECDSA(key.PrivateKey)
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iv := randentropy.GetEntropyCSPRNG(aes.BlockSize) // 16
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cipherText, err := aesCTRXOR(encryptKey, keyBytes, iv)
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if err != nil {
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return nil, err
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}
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mac := crypto.Keccak256(derivedKey[16:32], cipherText)
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scryptParamsJSON := make(map[string]interface{}, 5)
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scryptParamsJSON["n"] = scryptN
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scryptParamsJSON["r"] = scryptR
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scryptParamsJSON["p"] = scryptP
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scryptParamsJSON["dklen"] = scryptDKLen
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scryptParamsJSON["salt"] = hex.EncodeToString(salt)
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cipherParamsJSON := cipherparamsJSON{
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IV: hex.EncodeToString(iv),
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}
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cryptoStruct := cryptoJSON{
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Cipher: "aes-128-ctr",
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CipherText: hex.EncodeToString(cipherText),
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CipherParams: cipherParamsJSON,
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KDF: "scrypt",
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KDFParams: scryptParamsJSON,
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MAC: hex.EncodeToString(mac),
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}
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encryptedKeyJSONV3 := encryptedKeyJSONV3{
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hex.EncodeToString(key.Address[:]),
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cryptoStruct,
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key.Id.String(),
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version,
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}
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return json.Marshal(encryptedKeyJSONV3)
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}
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// DecryptKey decrypts a key from a json blob, returning the private key itself.
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func DecryptKey(keyjson []byte, auth string) (*Key, error) {
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// Parse the json into a simple map to fetch the key version
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m := make(map[string]interface{})
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if err := json.Unmarshal(keyjson, &m); err != nil {
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return nil, err
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}
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// Depending on the version try to parse one way or another
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var (
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keyBytes, keyId []byte
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err error
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)
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if version, ok := m["version"].(string); ok && version == "1" {
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k := new(encryptedKeyJSONV1)
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if err := json.Unmarshal(keyjson, k); err != nil {
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return nil, err
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}
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keyBytes, keyId, err = decryptKeyV1(k, auth)
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} else {
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k := new(encryptedKeyJSONV3)
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if err := json.Unmarshal(keyjson, k); err != nil {
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return nil, err
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}
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keyBytes, keyId, err = decryptKeyV3(k, auth)
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}
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// Handle any decryption errors and return the key
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if err != nil {
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return nil, err
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}
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key := crypto.ToECDSA(keyBytes)
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return &Key{
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Id: uuid.UUID(keyId),
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Address: crypto.PubkeyToAddress(key.PublicKey),
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PrivateKey: key,
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}, nil
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}
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func decryptKeyV3(keyProtected *encryptedKeyJSONV3, auth string) (keyBytes []byte, keyId []byte, err error) {
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if keyProtected.Version != version {
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return nil, nil, fmt.Errorf("Version not supported: %v", keyProtected.Version)
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}
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if keyProtected.Crypto.Cipher != "aes-128-ctr" {
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return nil, nil, fmt.Errorf("Cipher not supported: %v", keyProtected.Crypto.Cipher)
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}
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keyId = uuid.Parse(keyProtected.Id)
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mac, err := hex.DecodeString(keyProtected.Crypto.MAC)
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if err != nil {
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return nil, nil, err
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}
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iv, err := hex.DecodeString(keyProtected.Crypto.CipherParams.IV)
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if err != nil {
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return nil, nil, err
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}
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cipherText, err := hex.DecodeString(keyProtected.Crypto.CipherText)
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if err != nil {
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return nil, nil, err
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}
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derivedKey, err := getKDFKey(keyProtected.Crypto, auth)
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if err != nil {
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return nil, nil, err
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}
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calculatedMAC := crypto.Keccak256(derivedKey[16:32], cipherText)
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if !bytes.Equal(calculatedMAC, mac) {
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return nil, nil, errors.New("Decryption failed: MAC mismatch")
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}
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plainText, err := aesCTRXOR(derivedKey[:16], cipherText, iv)
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if err != nil {
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return nil, nil, err
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}
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return plainText, keyId, err
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}
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func decryptKeyV1(keyProtected *encryptedKeyJSONV1, auth string) (keyBytes []byte, keyId []byte, err error) {
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keyId = uuid.Parse(keyProtected.Id)
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mac, err := hex.DecodeString(keyProtected.Crypto.MAC)
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if err != nil {
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return nil, nil, err
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}
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iv, err := hex.DecodeString(keyProtected.Crypto.CipherParams.IV)
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if err != nil {
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return nil, nil, err
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}
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cipherText, err := hex.DecodeString(keyProtected.Crypto.CipherText)
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if err != nil {
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return nil, nil, err
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}
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derivedKey, err := getKDFKey(keyProtected.Crypto, auth)
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if err != nil {
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return nil, nil, err
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}
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calculatedMAC := crypto.Keccak256(derivedKey[16:32], cipherText)
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if !bytes.Equal(calculatedMAC, mac) {
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return nil, nil, errors.New("Decryption failed: MAC mismatch")
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}
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plainText, err := aesCBCDecrypt(crypto.Keccak256(derivedKey[:16])[:16], cipherText, iv)
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if err != nil {
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return nil, nil, err
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}
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return plainText, keyId, err
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}
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func getKDFKey(cryptoJSON cryptoJSON, auth string) ([]byte, error) {
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authArray := []byte(auth)
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salt, err := hex.DecodeString(cryptoJSON.KDFParams["salt"].(string))
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if err != nil {
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return nil, err
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}
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dkLen := ensureInt(cryptoJSON.KDFParams["dklen"])
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if cryptoJSON.KDF == "scrypt" {
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n := ensureInt(cryptoJSON.KDFParams["n"])
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r := ensureInt(cryptoJSON.KDFParams["r"])
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p := ensureInt(cryptoJSON.KDFParams["p"])
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return scrypt.Key(authArray, salt, n, r, p, dkLen)
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} else if cryptoJSON.KDF == "pbkdf2" {
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c := ensureInt(cryptoJSON.KDFParams["c"])
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prf := cryptoJSON.KDFParams["prf"].(string)
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if prf != "hmac-sha256" {
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return nil, fmt.Errorf("Unsupported PBKDF2 PRF: %s", prf)
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}
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key := pbkdf2.Key(authArray, salt, c, dkLen, sha256.New)
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return key, nil
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}
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return nil, fmt.Errorf("Unsupported KDF: %s", cryptoJSON.KDF)
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}
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// TODO: can we do without this when unmarshalling dynamic JSON?
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// why do integers in KDF params end up as float64 and not int after
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// unmarshal?
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func ensureInt(x interface{}) int {
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res, ok := x.(int)
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if !ok {
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res = int(x.(float64))
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}
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return res
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}
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