Address pull request comments; key header and hex encoding

* Remove key header from unencrypted key file format and replace
  it with a version field
* Change encoding of bytes in key files from base64 to hex

Author: Gustav Simonsson

crypto/key.go

@@ -26,13 +26,18 @@ package crypto
 import (
 	"bytes"
 	"crypto/ecdsa"
+	"encoding/hex"
 	"encoding/json"
 	"io"
 
 	"code.google.com/p/go-uuid/uuid"
 	"github.com/ethereum/go-ethereum/common"
 )
 
+const (
+	version = "1"
+)
+
 type Key struct {
 	Id uuid.UUID // Version 4 "random" for unique id not derived from key data
 	// to simplify lookups we also store the address
@@ -43,29 +48,31 @@ type Key struct {
 }
 
 type plainKeyJSON struct {
-	Id         []byte
-	Address    []byte
-	PrivateKey []byte
+	Version    string
+	Id         string
+	Address    string
+	PrivateKey string
 }
 
 type encryptedKeyJSON struct {
-	Id      []byte
-	Address []byte
+	Version string
+	Id      string
+	Address string
 	Crypto  cipherJSON
 }
 
 type cipherJSON struct {
-	MAC        []byte
-	Salt       []byte
-	IV         []byte
+	MAC        string
+	Salt       string
+	IV         string
 	KeyHeader  keyHeaderJSON
-	CipherText []byte
+	CipherText string
 }
 
 type keyHeaderJSON struct {
 	Version   string
 	Kdf       string
-	KdfParams scryptParamsJSON // TODO: make more generic?
+	KdfParams scryptParamsJSON
 }
 
 type scryptParamsJSON struct {
@@ -78,9 +85,10 @@ type scryptParamsJSON struct {
 
 func (k *Key) MarshalJSON() (j []byte, err error) {
 	jStruct := plainKeyJSON{
-		k.Id,
-		k.Address.Bytes(),
-		FromECDSA(k.PrivateKey),
+		version,
+		k.Id.String(),
+		hex.EncodeToString(k.Address[:]),
+		hex.EncodeToString(FromECDSA(k.PrivateKey)),
 	}
 	j, err = json.Marshal(jStruct)
 	return j, err
@@ -94,12 +102,22 @@ func (k *Key) UnmarshalJSON(j []byte) (err error) {
 	}
 
 	u := new(uuid.UUID)
-	*u = keyJSON.Id
+	*u = uuid.Parse(keyJSON.Id)
 	k.Id = *u
-	k.Address = common.BytesToAddress(keyJSON.Address)
-	k.PrivateKey = ToECDSA(keyJSON.PrivateKey)
+	addr, err := hex.DecodeString(keyJSON.Address)
+	if err != nil {
+		return err
+	}
+
+	privkey, err := hex.DecodeString(keyJSON.PrivateKey)
+	if err != nil {
+		return err
+	}
+
+	k.Address = common.BytesToAddress(addr)
+	k.PrivateKey = ToECDSA(privkey)
 
-	return err
+	return nil
 }
 
 func NewKeyFromECDSA(privateKeyECDSA *ecdsa.PrivateKey) *Key {

crypto/key_store_passphrase.go

@@ -68,6 +68,7 @@ import (
 	"bytes"
 	"crypto/aes"
 	"crypto/cipher"
+	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"io"
@@ -164,15 +165,16 @@ func (ks keyStorePassphrase) StoreKey(key *Key, auth string) (err error) {
 	mac := Sha3(keyHeaderJSONStr, derivedKey[16:32], cipherText)
 
 	cipherStruct := cipherJSON{
-		mac,
-		salt,
-		iv,
+		hex.EncodeToString(mac),
+		hex.EncodeToString(salt),
+		hex.EncodeToString(iv),
 		keyHeaderJSON,
-		cipherText,
+		hex.EncodeToString(cipherText),
 	}
 	keyStruct := encryptedKeyJSON{
-		key.Id,
-		key.Address.Bytes(),
+		version,
+		key.Id.String(),
+		hex.EncodeToString(key.Address[:]),
 		cipherStruct,
 	}
 	keyJSON, err := json.Marshal(keyStruct)
@@ -190,7 +192,7 @@ func (ks keyStorePassphrase) DeleteKey(keyAddr common.Address, auth string) (err
 		return err
 	}
 
-	keyDirPath := filepath.Join(ks.keysDirPath, keyAddr.Hex())
+	keyDirPath := filepath.Join(ks.keysDirPath, hex.EncodeToString(keyAddr[:]))
 	return os.RemoveAll(keyDirPath)
 }
 
@@ -203,12 +205,28 @@ func DecryptKey(ks keyStorePassphrase, keyAddr common.Address, auth string) (key
 	keyProtected := new(encryptedKeyJSON)
 	err = json.Unmarshal(fileContent, keyProtected)
 
-	keyId = keyProtected.Id
-	mac := keyProtected.Crypto.MAC
-	salt := keyProtected.Crypto.Salt
-	iv := keyProtected.Crypto.IV
+	keyId = uuid.Parse(keyProtected.Id)
+
+	mac, err := hex.DecodeString(keyProtected.Crypto.MAC)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	salt, err := hex.DecodeString(keyProtected.Crypto.Salt)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	iv, err := hex.DecodeString(keyProtected.Crypto.IV)
+	if err != nil {
+		return nil, nil, err
+	}
+
 	keyHeader := keyProtected.Crypto.KeyHeader
-	cipherText := keyProtected.Crypto.CipherText
+	cipherText, err := hex.DecodeString(keyProtected.Crypto.CipherText)
+	if err != nil {
+		return nil, nil, err
+	}
 
 	// used in MAC
 	keyHeaderJSONStr, err := json.Marshal(keyHeader)

crypto/key_store_plain.go

@@ -98,12 +98,12 @@ func (ks keyStorePlain) DeleteKey(keyAddr common.Address, auth string) (err erro
 }
 
 func GetKeyFile(keysDirPath string, keyAddr common.Address) (fileContent []byte, err error) {
-	fileName := keyAddr.Hex()
+	fileName := hex.EncodeToString(keyAddr[:])
 	return ioutil.ReadFile(filepath.Join(keysDirPath, fileName, fileName))
 }
 
 func WriteKeyFile(addr common.Address, keysDirPath string, content []byte) (err error) {
-	addrHex := addr.Hex()
+	addrHex := hex.EncodeToString(addr[:])
 	keyDirPath := filepath.Join(keysDirPath, addrHex)
 	keyFilePath := filepath.Join(keyDirPath, addrHex)
 	err = os.MkdirAll(keyDirPath, 0700) // read, write and dir search for user