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-rw-r--r--accounts/keystore/keystore_passphrase.go305
1 files changed, 305 insertions, 0 deletions
diff --git a/accounts/keystore/keystore_passphrase.go b/accounts/keystore/keystore_passphrase.go
new file mode 100644
index 000000000..8ef510fcf
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+++ b/accounts/keystore/keystore_passphrase.go
@@ -0,0 +1,305 @@
+// Copyright 2014 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/>.
+
+/*
+
+This key store behaves as KeyStorePlain with the difference that
+the private key is encrypted and on disk uses another JSON encoding.
+
+The crypto is documented at https://github.com/ethereum/wiki/wiki/Web3-Secret-Storage-Definition
+
+*/
+
+package keystore
+
+import (
+ "bytes"
+ "crypto/aes"
+ "crypto/sha256"
+ "encoding/hex"
+ "encoding/json"
+ "fmt"
+ "io/ioutil"
+ "path/filepath"
+
+ "github.com/ethereum/go-ethereum/common"
+ "github.com/ethereum/go-ethereum/crypto"
+ "github.com/ethereum/go-ethereum/crypto/randentropy"
+ "github.com/pborman/uuid"
+ "golang.org/x/crypto/pbkdf2"
+ "golang.org/x/crypto/scrypt"
+)
+
+const (
+ keyHeaderKDF = "scrypt"
+
+ // StandardScryptN is the N parameter of Scrypt encryption algorithm, using 256MB
+ // memory and taking approximately 1s CPU time on a modern processor.
+ StandardScryptN = 1 << 18
+
+ // StandardScryptP is the P parameter of Scrypt encryption algorithm, using 256MB
+ // memory and taking approximately 1s CPU time on a modern processor.
+ StandardScryptP = 1
+
+ // LightScryptN is the N parameter of Scrypt encryption algorithm, using 4MB
+ // memory and taking approximately 100ms CPU time on a modern processor.
+ LightScryptN = 1 << 12
+
+ // LightScryptP is the P parameter of Scrypt encryption algorithm, using 4MB
+ // memory and taking approximately 100ms CPU time on a modern processor.
+ LightScryptP = 6
+
+ scryptR = 8
+ scryptDKLen = 32
+)
+
+type keyStorePassphrase struct {
+ keysDirPath string
+ scryptN int
+ scryptP int
+}
+
+func (ks keyStorePassphrase) GetKey(addr common.Address, filename, auth string) (*Key, error) {
+ // Load the key from the keystore and decrypt its contents
+ keyjson, err := ioutil.ReadFile(filename)
+ 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 key.Address != addr {
+ return nil, fmt.Errorf("key content mismatch: have account %x, want %x", key.Address, addr)
+ }
+ return key, nil
+}
+
+func (ks keyStorePassphrase) StoreKey(filename string, key *Key, auth string) error {
+ keyjson, err := EncryptKey(key, auth, ks.scryptN, ks.scryptP)
+ if err != nil {
+ return err
+ }
+ return writeKeyFile(filename, keyjson)
+}
+
+func (ks keyStorePassphrase) JoinPath(filename string) string {
+ if filepath.IsAbs(filename) {
+ return filename
+ } else {
+ return filepath.Join(ks.keysDirPath, filename)
+ }
+}
+
+// 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]
+ keyBytes0 := crypto.FromECDSA(key.PrivateKey)
+ keyBytes := common.LeftPadBytes(keyBytes0, 32)
+
+ iv := randentropy.GetEntropyCSPRNG(aes.BlockSize) // 16
+ cipherText, err := aesCTRXOR(encryptKey, keyBytes, iv)
+ if err != nil {
+ return nil, err
+ }
+ mac := crypto.Keccak256(derivedKey[16:32], cipherText)
+
+ scryptParamsJSON := make(map[string]interface{}, 5)
+ scryptParamsJSON["n"] = scryptN
+ scryptParamsJSON["r"] = scryptR
+ scryptParamsJSON["p"] = scryptP
+ scryptParamsJSON["dklen"] = scryptDKLen
+ scryptParamsJSON["salt"] = hex.EncodeToString(salt)
+
+ cipherParamsJSON := cipherparamsJSON{
+ IV: hex.EncodeToString(iv),
+ }
+
+ cryptoStruct := cryptoJSON{
+ Cipher: "aes-128-ctr",
+ CipherText: hex.EncodeToString(cipherText),
+ CipherParams: cipherParamsJSON,
+ KDF: "scrypt",
+ KDFParams: scryptParamsJSON,
+ MAC: hex.EncodeToString(mac),
+ }
+ encryptedKeyJSONV3 := encryptedKeyJSONV3{
+ hex.EncodeToString(key.Address[:]),
+ cryptoStruct,
+ key.Id.String(),
+ version,
+ }
+ return json.Marshal(encryptedKeyJSONV3)
+}
+
+// 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{})
+ if err := json.Unmarshal(keyjson, &m); err != nil {
+ return nil, err
+ }
+ // 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)
+ if err := json.Unmarshal(keyjson, k); err != nil {
+ return nil, err
+ }
+ keyBytes, keyId, err = decryptKeyV1(k, auth)
+ } else {
+ k := new(encryptedKeyJSONV3)
+ if err := json.Unmarshal(keyjson, k); err != nil {
+ return nil, err
+ }
+ keyBytes, keyId, err = decryptKeyV3(k, auth)
+ }
+ // Handle any decryption errors and return the key
+ if err != nil {
+ return nil, err
+ }
+ key := crypto.ToECDSA(keyBytes)
+ return &Key{
+ Id: uuid.UUID(keyId),
+ Address: crypto.PubkeyToAddress(key.PublicKey),
+ PrivateKey: key,
+ }, nil
+}
+
+func decryptKeyV3(keyProtected *encryptedKeyJSONV3, auth string) (keyBytes []byte, keyId []byte, err error) {
+ if keyProtected.Version != version {
+ return nil, nil, fmt.Errorf("Version not supported: %v", keyProtected.Version)
+ }
+
+ if keyProtected.Crypto.Cipher != "aes-128-ctr" {
+ return nil, nil, fmt.Errorf("Cipher not supported: %v", keyProtected.Crypto.Cipher)
+ }
+
+ keyId = uuid.Parse(keyProtected.Id)
+ mac, err := hex.DecodeString(keyProtected.Crypto.MAC)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ iv, err := hex.DecodeString(keyProtected.Crypto.CipherParams.IV)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ cipherText, err := hex.DecodeString(keyProtected.Crypto.CipherText)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ derivedKey, err := getKDFKey(keyProtected.Crypto, auth)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ calculatedMAC := crypto.Keccak256(derivedKey[16:32], cipherText)
+ if !bytes.Equal(calculatedMAC, mac) {
+ return nil, nil, ErrDecrypt
+ }
+
+ plainText, err := aesCTRXOR(derivedKey[:16], cipherText, iv)
+ if err != nil {
+ return nil, nil, err
+ }
+ return plainText, keyId, err
+}
+
+func decryptKeyV1(keyProtected *encryptedKeyJSONV1, auth string) (keyBytes []byte, keyId []byte, err error) {
+ keyId = uuid.Parse(keyProtected.Id)
+ mac, err := hex.DecodeString(keyProtected.Crypto.MAC)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ iv, err := hex.DecodeString(keyProtected.Crypto.CipherParams.IV)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ cipherText, err := hex.DecodeString(keyProtected.Crypto.CipherText)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ derivedKey, err := getKDFKey(keyProtected.Crypto, auth)
+ if err != nil {
+ return nil, nil, err
+ }
+
+ calculatedMAC := crypto.Keccak256(derivedKey[16:32], cipherText)
+ if !bytes.Equal(calculatedMAC, mac) {
+ return nil, nil, ErrDecrypt
+ }
+
+ plainText, err := aesCBCDecrypt(crypto.Keccak256(derivedKey[:16])[:16], cipherText, iv)
+ if err != nil {
+ return nil, nil, err
+ }
+ return plainText, keyId, err
+}
+
+func getKDFKey(cryptoJSON cryptoJSON, auth string) ([]byte, error) {
+ authArray := []byte(auth)
+ salt, err := hex.DecodeString(cryptoJSON.KDFParams["salt"].(string))
+ if err != nil {
+ return nil, err
+ }
+ dkLen := ensureInt(cryptoJSON.KDFParams["dklen"])
+
+ if cryptoJSON.KDF == "scrypt" {
+ n := ensureInt(cryptoJSON.KDFParams["n"])
+ r := ensureInt(cryptoJSON.KDFParams["r"])
+ p := ensureInt(cryptoJSON.KDFParams["p"])
+ return scrypt.Key(authArray, salt, n, r, p, dkLen)
+
+ } else if cryptoJSON.KDF == "pbkdf2" {
+ c := ensureInt(cryptoJSON.KDFParams["c"])
+ prf := cryptoJSON.KDFParams["prf"].(string)
+ if prf != "hmac-sha256" {
+ return nil, fmt.Errorf("Unsupported PBKDF2 PRF: %s", prf)
+ }
+ key := pbkdf2.Key(authArray, salt, c, dkLen, sha256.New)
+ return key, nil
+ }
+
+ return nil, fmt.Errorf("Unsupported KDF: %s", cryptoJSON.KDF)
+}
+
+// TODO: can we do without this when unmarshalling dynamic JSON?
+// why do integers in KDF params end up as float64 and not int after
+// unmarshal?
+func ensureInt(x interface{}) int {
+ res, ok := x.(int)
+ if !ok {
+ res = int(x.(float64))
+ }
+ return res
+}