lnd+server+netann: use signing interface in node signer

netann/node_signer.go

@@ -6,25 +6,21 @@ import (
 	"github.com/btcsuite/btcd/btcec"
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/lightningnetwork/lnd/input"
+	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnwallet"
 )
 
 // NodeSigner is an implementation of the MessageSigner interface backed by the
 // identity private key of running lnd node.
 type NodeSigner struct {
-	privKey *btcec.PrivateKey
+	keySigner keychain.SingleKeyDigestSigner
 }
 
 // NewNodeSigner creates a new instance of the NodeSigner backed by the target
 // private key.
-func NewNodeSigner(key *btcec.PrivateKey) *NodeSigner {
-	priv := &btcec.PrivateKey{}
-	priv.Curve = btcec.S256()
-	priv.PublicKey.X = key.X
-	priv.PublicKey.Y = key.Y
-	priv.D = key.D
+func NewNodeSigner(keySigner keychain.SingleKeyDigestSigner) *NodeSigner {
 	return &NodeSigner{
-		privKey: priv,
+		keySigner: keySigner,
 	}
 }
 
@@ -36,13 +32,14 @@ func (n *NodeSigner) SignMessage(pubKey *btcec.PublicKey,
 
 	// If this isn't our identity public key, then we'll exit early with an
 	// error as we can't sign with this key.
-	if !pubKey.IsEqual(n.privKey.PubKey()) {
+	if !pubKey.IsEqual(n.keySigner.PubKey()) {
 		return nil, fmt.Errorf("unknown public key")
 	}
 
 	// Otherwise, we'll sign the dsha256 of the target message.
-	digest := chainhash.DoubleHashB(msg)
-	sig, err := n.privKey.Sign(digest)
+	var digest [32]byte
+	copy(digest[:], chainhash.DoubleHashB(msg))
+	sig, err := n.keySigner.SignDigest(digest)
 	if err != nil {
 		return nil, fmt.Errorf("can't sign the message: %v", err)
 	}
@@ -63,14 +60,11 @@ func (n *NodeSigner) SignCompact(msg []byte) ([]byte, error) {
 // SignDigestCompact signs the provided message digest under the resident
 // node's private key. The returned signature is a pubkey-recoverable signature.
 func (n *NodeSigner) SignDigestCompact(hash []byte) ([]byte, error) {
+	var digest [32]byte
+	copy(digest[:], hash)
 
-	// Should the signature reference a compressed public key or not.
-	isCompressedKey := true
-
-	// btcec.SignCompact returns a pubkey-recoverable signature
-	sig, err := btcec.SignCompact(
-		btcec.S256(), n.privKey, hash, isCompressedKey,
-	)
+	// keychain.SignDigestCompact returns a pubkey-recoverable signature.
+	sig, err := n.keySigner.SignDigestCompact(digest)
 	if err != nil {
 		return nil, fmt.Errorf("can't sign the hash: %v", err)
 	}