Add key header to encrypted keys

* Add key header containing key version, kdf and kdf params
* Store key header as JSON in the key file
* Read in KDF params from key header
* Include key header in MAC calculation and MAC verification

1 files changed, 19 insertions, 4 deletions

diff --git a/crypto/key.go b/crypto/key.go
index 5e1f3637e..067a5a294 100644
--- a/crypto/key.go
+++ b/crypto/key.go
@@ -48,17 +48,32 @@ type plainKeyJSON struct {
 	PrivateKey []byte
 }
 
+type encryptedKeyJSON struct {
+	Id      []byte
+	Address []byte
+	Crypto  cipherJSON
+}
+
 type cipherJSON struct {
 	MAC        []byte
 	Salt       []byte
 	IV         []byte
+	KeyHeader  keyHeaderJSON
 	CipherText []byte
 }
 
-type encryptedKeyJSON struct {
-	Id      []byte
-	Address []byte
-	Crypto  cipherJSON
+type keyHeaderJSON struct {
+	Version   string
+	Kdf       string
+	KdfParams scryptParamsJSON // TODO: make more generic?
+}
+
+type scryptParamsJSON struct {
+	N       int
+	R       int
+	P       int
+	DkLen   int
+	SaltLen int
 }
 
 func (k *Key) MarshalJSON() (j []byte, err error) {