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- // 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/rand"
- "crypto/sha256"
- "encoding/hex"
- "encoding/json"
- "fmt"
- "io"
- "io/ioutil"
- "os"
- "path/filepath"
- "github.com/ethereum/go-ethereum/accounts"
- "github.com/ethereum/go-ethereum/common"
- "github.com/ethereum/go-ethereum/common/math"
- "github.com/ethereum/go-ethereum/crypto"
- "github.com/google/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
- // skipKeyFileVerification disables the security-feature which does
- // reads and decrypts any newly created keyfiles. This should be 'false' in all
- // cases except tests -- setting this to 'true' is not recommended.
- skipKeyFileVerification bool
- }
- 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
- }
- // StoreKey generates a key, encrypts with 'auth' and stores in the given directory
- func StoreKey(dir, auth string, scryptN, scryptP int) (accounts.Account, error) {
- _, a, err := storeNewKey(&keyStorePassphrase{dir, scryptN, scryptP, false}, rand.Reader, auth)
- return a, err
- }
- 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
- }
- // Write into temporary file
- tmpName, err := writeTemporaryKeyFile(filename, keyjson)
- if err != nil {
- return err
- }
- if !ks.skipKeyFileVerification {
- // Verify that we can decrypt the file with the given password.
- _, err = ks.GetKey(key.Address, tmpName, auth)
- if err != nil {
- msg := "An error was encountered when saving and verifying the keystore file. \n" +
- "This indicates that the keystore is corrupted. \n" +
- "The corrupted file is stored at \n%v\n" +
- "Please file a ticket at:\n\n" +
- "https://github.com/ethereum/go-ethereum/issues." +
- "The error was : %s"
- //lint:ignore ST1005 This is a message for the user
- return fmt.Errorf(msg, tmpName, err)
- }
- }
- return os.Rename(tmpName, filename)
- }
- func (ks keyStorePassphrase) JoinPath(filename string) string {
- if filepath.IsAbs(filename) {
- return filename
- }
- return filepath.Join(ks.keysDirPath, filename)
- }
- // Encryptdata encrypts the data given as 'data' with the password 'auth'.
- func EncryptDataV3(data, auth []byte, scryptN, scryptP int) (CryptoJSON, error) {
- salt := make([]byte, 32)
- if _, err := io.ReadFull(rand.Reader, salt); err != nil {
- panic("reading from crypto/rand failed: " + err.Error())
- }
- derivedKey, err := scrypt.Key(auth, salt, scryptN, scryptR, scryptP, scryptDKLen)
- if err != nil {
- return CryptoJSON{}, err
- }
- encryptKey := derivedKey[:16]
- iv := make([]byte, aes.BlockSize) // 16
- if _, err := io.ReadFull(rand.Reader, iv); err != nil {
- panic("reading from crypto/rand failed: " + err.Error())
- }
- cipherText, err := aesCTRXOR(encryptKey, data, iv)
- if err != nil {
- return CryptoJSON{}, 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: keyHeaderKDF,
- KDFParams: scryptParamsJSON,
- MAC: hex.EncodeToString(mac),
- }
- return cryptoStruct, nil
- }
- // 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) {
- keyBytes := math.PaddedBigBytes(key.PrivateKey.D, 32)
- cryptoStruct, err := EncryptDataV3(keyBytes, []byte(auth), scryptN, scryptP)
- if err != nil {
- return nil, err
- }
- 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.ToECDSAUnsafe(keyBytes)
- id, err := uuid.FromBytes(keyId)
- if err != nil {
- return nil, err
- }
- return &Key{
- Id: id,
- Address: crypto.PubkeyToAddress(key.PublicKey),
- PrivateKey: key,
- }, nil
- }
- func DecryptDataV3(cryptoJson CryptoJSON, auth string) ([]byte, error) {
- if cryptoJson.Cipher != "aes-128-ctr" {
- return nil, fmt.Errorf("cipher not supported: %v", cryptoJson.Cipher)
- }
- mac, err := hex.DecodeString(cryptoJson.MAC)
- if err != nil {
- return nil, err
- }
- iv, err := hex.DecodeString(cryptoJson.CipherParams.IV)
- if err != nil {
- return nil, err
- }
- cipherText, err := hex.DecodeString(cryptoJson.CipherText)
- if err != nil {
- return nil, err
- }
- derivedKey, err := getKDFKey(cryptoJson, auth)
- if err != nil {
- return nil, err
- }
- calculatedMAC := crypto.Keccak256(derivedKey[16:32], cipherText)
- if !bytes.Equal(calculatedMAC, mac) {
- return nil, ErrDecrypt
- }
- plainText, err := aesCTRXOR(derivedKey[:16], cipherText, iv)
- if err != nil {
- return nil, err
- }
- return plainText, err
- }
- 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)
- }
- keyUUID, err := uuid.Parse(keyProtected.Id)
- if err != nil {
- return nil, nil, err
- }
- keyId = keyUUID[:]
- plainText, err := DecryptDataV3(keyProtected.Crypto, auth)
- if err != nil {
- return nil, nil, err
- }
- return plainText, keyId, err
- }
- func decryptKeyV1(keyProtected *encryptedKeyJSONV1, auth string) (keyBytes []byte, keyId []byte, err error) {
- keyUUID, err := uuid.Parse(keyProtected.Id)
- if err != nil {
- return nil, nil, err
- }
- keyId = keyUUID[:]
- 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 == keyHeaderKDF {
- 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
- }
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