Add key header to unencrypted key file

crypto/key.go

@@ -45,27 +45,28 @@ type Key struct {
 type plainKeyJSON struct {
 	Id         []byte
 	Address    []byte
+	KeyHeader  keyHeaderJSON
 	PrivateKey []byte
 }
 
 type encryptedKeyJSON struct {
-	Id      []byte
-	Address []byte
-	Crypto  cipherJSON
+	Id        []byte
+	Address   []byte
+	KeyHeader keyHeaderJSON
+	Crypto    cipherJSON
 }
 
 type cipherJSON struct {
 	MAC        []byte
 	Salt       []byte
 	IV         []byte
-	KeyHeader  keyHeaderJSON
 	CipherText []byte
 }
 
 type keyHeaderJSON struct {
 	Version   string
 	Kdf       string
-	KdfParams scryptParamsJSON // TODO: make more generic?
+	KdfParams *scryptParamsJSON // TODO: make more generic?
 }
 
 type scryptParamsJSON struct {
@@ -77,9 +78,15 @@ type scryptParamsJSON struct {
 }
 
 func (k *Key) MarshalJSON() (j []byte, err error) {
+	keyHeader := keyHeaderJSON{
+		Version:   "1",
+		Kdf:       "",
+		KdfParams: nil,
+	}
 	jStruct := plainKeyJSON{
 		k.Id,
 		k.Address.Bytes(),
+		keyHeader,
 		FromECDSA(k.PrivateKey),
 	}
 	j, err = json.Marshal(jStruct)