From 51ff07956b3c249d9badfccf3c1edca38943ac63 Mon Sep 17 00:00:00 2001
From: ardevd <ardevd@users.noreply.github.com>
Date: Sun, 14 Jan 2024 22:39:46 +0100
Subject: [PATCH] client: implemented messaging signing.

added support for the main RPC implementation of message signing.
---
 lightning_client.go      | 24 ++++++++++++++++++++++++
 macaroon_recipes_test.go |  2 +-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/lightning_client.go b/lightning_client.go
index d6c1316..f326c05 100644
--- a/lightning_client.go
+++ b/lightning_client.go
@@ -271,6 +271,13 @@ type LightningClient interface {
 	// relevant to the wallet are sent over.
 	SubscribeTransactions(ctx context.Context) (<-chan Transaction,
 		<-chan error, error)
+
+	// SignMessage signs a message with this node's private key.
+	// The returned signature string is zbase32 encoded and pubkey
+	// recoverable, meaning that only the message digest and signature
+	// are needed for verification.
+	SignMessage(ctx context.Context, data []byte) (string,
+		error)
 }
 
 // Info contains info about the connected lnd node.
@@ -4132,6 +4139,23 @@ func (s *lightningClient) SendCustomMessage(ctx context.Context,
 	return err
 }
 
+// SignMessage signs a message with this node's private key.
+// The returned signature string is zbase32 encoded and pubkey
+// recoverable, meaning that only the message digest and signature
+// are needed for verification.
+func (s *lightningClient) SignMessage(ctx context.Context,
+	data []byte) (string, error) {
+
+	rpcCtx := s.adminMac.WithMacaroonAuth(ctx)
+	rpcReq := &lnrpc.SignMessageRequest{Msg: data}
+	rpcRes, err := s.client.SignMessage(rpcCtx, rpcReq)
+	if err != nil {
+		return "", err
+	}
+
+	return rpcRes.Signature, nil
+}
+
 // SubscribeCustomMessages subscribes to a stream of custom messages, optionally
 // filtering by peer and message type. The channels returned will be closed
 // when the subscription exits.
diff --git a/macaroon_recipes_test.go b/macaroon_recipes_test.go
index 95e033d..ab1a2d3 100644
--- a/macaroon_recipes_test.go
+++ b/macaroon_recipes_test.go
@@ -12,7 +12,7 @@ import (
 
 var (
 	expectedPermissions = map[string]int{
-		"lnrpc":       11,
+		"lnrpc":       12,
 		"chainrpc":    1,
 		"invoicesrpc": 2,
 		"routerrpc":   2,