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Merge pull request #2221 from karalabe/expost-key-decryption

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crypto: expose key decryption method to parse a string direclty
This commit is contained in:
Péter Szilágyi 2016-03-01 11:01:06 +02:00
commit 8255afbc75
3 changed files with 127 additions and 58 deletions
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116
crypto/key_store_passphrase.go
View File

@ -34,7 +34,6 @@ import (
"errors"
"fmt"
"io"
"reflect"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto/randentropy"
@ -62,12 +61,10 @@ type keyStorePassphrase struct {
keysDirPath string
scryptN int
scryptP int
scryptR int
scryptDKLen int
}
func NewKeyStorePassphrase(path string, scryptN int, scryptP int) KeyStore {
return &keyStorePassphrase{path, scryptN, scryptP, scryptR, scryptDKLen}
return &keyStorePassphrase{path, scryptN, scryptP}
}
func (ks keyStorePassphrase) GenerateNewKey(rand io.Reader, auth string) (key *Key, err error) {
@ -75,15 +72,7 @@ func (ks keyStorePassphrase) GenerateNewKey(rand io.Reader, auth string) (key *K
}
func (ks keyStorePassphrase) GetKey(keyAddr common.Address, auth string) (key *Key, err error) {
keyBytes, keyId, err := decryptKeyFromFile(ks.keysDirPath, keyAddr, auth)
if err == nil {
key = &Key{
Id: uuid.UUID(keyId),
Address: keyAddr,
PrivateKey: ToECDSA(keyBytes),
}
}
return
return decryptKeyFromFile(ks.keysDirPath, keyAddr, auth)
}
func (ks keyStorePassphrase) Cleanup(keyAddr common.Address) (err error) {
@ -94,29 +83,38 @@ func (ks keyStorePassphrase) GetKeyAddresses() (addresses []common.Address, err
return getKeyAddresses(ks.keysDirPath)
}
func (ks keyStorePassphrase) StoreKey(key *Key, auth string) (err error) {
authArray := []byte(auth)
salt := randentropy.GetEntropyCSPRNG(32)
derivedKey, err := scrypt.Key(authArray, salt, ks.scryptN, ks.scryptR, ks.scryptP, ks.scryptDKLen)
func (ks keyStorePassphrase) StoreKey(key *Key, auth string) error {
keyjson, err := EncryptKey(key, auth, ks.scryptN, ks.scryptP)
if err != nil {
return err
}
return writeKeyFile(key.Address, ks.keysDirPath, keyjson)
}
// EncryptKey encrypts a key using the specified scrypt parameters into a json
// blob that can be decrypted later on.
func EncryptKey(key *Key, auth string, scryptN, scryptP int) ([]byte, error) {
authArray := []byte(auth)
salt := randentropy.GetEntropyCSPRNG(32)
derivedKey, err := scrypt.Key(authArray, salt, scryptN, scryptR, scryptP, scryptDKLen)
if err != nil {
return nil, err
}
encryptKey := derivedKey[:16]
keyBytes := FromECDSA(key.PrivateKey)
iv := randentropy.GetEntropyCSPRNG(aes.BlockSize) // 16
cipherText, err := aesCTRXOR(encryptKey, keyBytes, iv)
if err != nil {
return err
return nil, err
}
mac := Keccak256(derivedKey[16:32], cipherText)
scryptParamsJSON := make(map[string]interface{}, 5)
scryptParamsJSON["n"] = ks.scryptN
scryptParamsJSON["r"] = ks.scryptR
scryptParamsJSON["p"] = ks.scryptP
scryptParamsJSON["dklen"] = ks.scryptDKLen
scryptParamsJSON["n"] = scryptN
scryptParamsJSON["r"] = scryptR
scryptParamsJSON["p"] = scryptP
scryptParamsJSON["dklen"] = scryptDKLen
scryptParamsJSON["salt"] = hex.EncodeToString(salt)
cipherParamsJSON := cipherparamsJSON{
@ -137,47 +135,69 @@ func (ks keyStorePassphrase) StoreKey(key *Key, auth string) (err error) {
key.Id.String(),
version,
}
keyJSON, err := json.Marshal(encryptedKeyJSONV3)
if err != nil {
return err
}
return writeKeyFile(key.Address, ks.keysDirPath, keyJSON)
return json.Marshal(encryptedKeyJSONV3)
}
func (ks keyStorePassphrase) DeleteKey(keyAddr common.Address, auth string) (err error) {
func (ks keyStorePassphrase) DeleteKey(keyAddr common.Address, auth string) error {
// only delete if correct passphrase is given
_, _, err = decryptKeyFromFile(ks.keysDirPath, keyAddr, auth)
if err != nil {
if _, err := decryptKeyFromFile(ks.keysDirPath, keyAddr, auth); err != nil {
return err
}
return deleteKey(ks.keysDirPath, keyAddr)
}
func decryptKeyFromFile(keysDirPath string, keyAddr common.Address, auth string) (keyBytes []byte, keyId []byte, err error) {
// DecryptKey decrypts a key from a json blob, returning the private key itself.
func DecryptKey(keyjson []byte, auth string) (*Key, error) {
// Parse the json into a simple map to fetch the key version
m := make(map[string]interface{})
err = getKey(keysDirPath, keyAddr, &m)
if err != nil {
return
if err := json.Unmarshal(keyjson, &m); err != nil {
return nil, err
}
v := reflect.ValueOf(m["version"])
if v.Kind() == reflect.String && v.String() == "1" {
// Depending on the version try to parse one way or another
var (
keyBytes, keyId []byte
err error
)
if version, ok := m["version"].(string); ok && version == "1" {
k := new(encryptedKeyJSONV1)
err = getKey(keysDirPath, keyAddr, &k)
if err != nil {
return
if err := json.Unmarshal(keyjson, k); err != nil {
return nil, err
}
return decryptKeyV1(k, auth)
keyBytes, keyId, err = decryptKeyV1(k, auth)
} else {
k := new(encryptedKeyJSONV3)
err = getKey(keysDirPath, keyAddr, &k)
if err != nil {
return
if err := json.Unmarshal(keyjson, k); err != nil {
return nil, err
}
return decryptKeyV3(k, auth)
keyBytes, keyId, err = decryptKeyV3(k, auth)
}
// Handle any decryption errors and return the key
if err != nil {
return nil, err
}
key := ToECDSA(keyBytes)
return &Key{
Id: uuid.UUID(keyId),
Address: PubkeyToAddress(key.PublicKey),
PrivateKey: key,
}, nil
}
func decryptKeyFromFile(keysDirPath string, keyAddr common.Address, auth string) (*Key, error) {
// Load the key from the keystore and decrypt its contents
keyjson, err := getKeyFile(keysDirPath, keyAddr)
if err != nil {
return nil, err
}
key, err := DecryptKey(keyjson, auth)
if err != nil {
return nil, err
}
// Make sure we're really operating on the requested key (no swap attacks)
if keyAddr != key.Address {
return nil, fmt.Errorf("key content mismatch: have account %x, want %x", key.Address, keyAddr)
}
return key, nil
}
func decryptKeyV3(keyProtected *encryptedKeyJSONV3, auth string) (keyBytes []byte, keyId []byte, err error) {

51
crypto/key_store_passphrase_test.go Normal file
View File

@ -0,0 +1,51 @@
// Copyright 2016 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 (
"testing"
"github.com/ethereum/go-ethereum/common"
)
// Tests that a json key file can be decrypted and encrypted in multiple rounds.
func TestKeyEncryptDecrypt(t *testing.T) {
address := common.HexToAddress("f626acac23772cbe04dd578bee681b06bdefb9fa")
keyjson := []byte("{\"address\":\"f626acac23772cbe04dd578bee681b06bdefb9fa\",\"crypto\":{\"cipher\":\"aes-128-ctr\",\"ciphertext\":\"1bcf0ab9b14459795ce59f63e63255ffd84dc38d31614a5a78e37144d7e4a17f\",\"cipherparams\":{\"iv\":\"df4c7e225ee2d81adef522013e3fbe24\"},\"kdf\":\"scrypt\",\"kdfparams\":{\"dklen\":32,\"n\":262144,\"p\":1,\"r\":8,\"salt\":\"2909a99dd2bfa7079a4b40991773b1083f8512c0c55b9b63402ab0e3dc8db8b3\"},\"mac\":\"4ecf6a4ad92ae2c016cb7c44abade74799480c3303eb024661270dfefdbc7510\"},\"id\":\"b4718210-9a30-4883-b8a6-dbdd08bd0ceb\",\"version\":3}")
password := ""
// Do a few rounds of decryption and encryption
for i := 0; i < 3; i++ {
// Try a bad password first
if _, err := DecryptKey(keyjson, password+"bad"); err == nil {
t.Error("test %d: json key decrypted with bad password", i)
}
// Decrypt with the correct password
key, err := DecryptKey(keyjson, password)
if err != nil {
t.Errorf("test %d: json key failed to decrypt: %v", i, err)
}
if key.Address != address {
t.Errorf("test %d: key address mismatch: have %x, want %x", i, key.Address, address)
}
// Recrypt with a new password and start over
password += "new data appended"
if keyjson, err = EncryptKey(key, password, LightScryptN, LightScryptP); err != nil {
t.Errorf("test %d: failed to recrypt key %v", err)
}
}
}

18
crypto/key_store_plain.go
View File

@ -62,18 +62,16 @@ func GenerateNewKeyDefault(ks KeyStore, rand io.Reader, auth string) (key *Key,
return key, err
}
func (ks keyStorePlain) GetKey(keyAddr common.Address, auth string) (key *Key, err error) {
key = new(Key)
err = getKey(ks.keysDirPath, keyAddr, key)
return
}
func getKey(keysDirPath string, keyAddr common.Address, content interface{}) (err error) {
fileContent, err := getKeyFile(keysDirPath, keyAddr)
func (ks keyStorePlain) GetKey(keyAddr common.Address, auth string) (*Key, error) {
keyjson, err := getKeyFile(ks.keysDirPath, keyAddr)
if err != nil {
return
return nil, err
}
return json.Unmarshal(fileContent, content)
key := new(Key)
if err := json.Unmarshal(keyjson, key); err != nil {
return nil, err
}
return key, nil
}
func (ks keyStorePlain) GetKeyAddresses() (addresses []common.Address, err error) {