Add marshalling of private key

util/crypto/ed25519.go

@@ -55,6 +55,18 @@ func UnmarshalEd25519PublicKeyProto(bytes []byte) (PubKey, error) {
 	return UnmarshalEd25519PublicKey(msg.Data)
 }
 
+func UnmarshalEd25519PrivateKeyProto(bytes []byte) (PrivKey, error) {
+	msg := &cryptoproto.Key{}
+	err := proto.Unmarshal(bytes, msg)
+	if err != nil {
+		return nil, err
+	}
+	if msg.Type != cryptoproto.KeyType_Ed25519Private {
+		return nil, ErrIncorrectKeyType
+	}
+	return UnmarshalEd25519PrivateKey(msg.Data)
+}
+
 func NewSigningEd25519PubKeyFromBytes(bytes []byte) (PubKey, error) {
 	return UnmarshalEd25519PublicKey(bytes)
 }
@@ -114,6 +126,15 @@ func (k *Ed25519PrivKey) Sign(msg []byte) ([]byte, error) {
 	return ed25519.Sign(k.privKey, msg), nil
 }
 
+// Marshall marshalls the key into proto
+func (k *Ed25519PrivKey) Marshall() ([]byte, error) {
+	msg := &cryptoproto.Key{
+		Type: cryptoproto.KeyType_Ed25519Public,
+		Data: k.privKey,
+	}
+	return msg.Marshal()
+}
+
 // Decrypt decrypts the message
 func (k *Ed25519PrivKey) Decrypt(msg []byte) ([]byte, error) {
 	k.once.Do(func() {

util/crypto/key.go

@@ -27,6 +27,8 @@ type PrivKey interface {
 	Sign([]byte) ([]byte, error)
 	// GetPublic returns the associated public key
 	GetPublic() PubKey
+	// Marshall wraps key in proto encoding and marshalls it
+	Marshall() ([]byte, error)
 	// LibP2P returns libp2p model
 	LibP2P() (crypto.PrivKey, error)
 }