// 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/ava-labs/coreth/accounts" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/common/math" "github.com/ethereum/go-ethereum/crypto" "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 // 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) return &Key{ Id: uuid.UUID(keyId), 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) } keyId = uuid.Parse(keyProtected.Id) 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) { 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 == 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 }