Merge pull request #3812 from guggero/sign-custom

signrpc: sign and verify messages with custom key

lnrpc/signrpc/config_active.go

@@ -4,6 +4,7 @@ package signrpc
 
 import (
 	"github.com/lightningnetwork/lnd/input"
+	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/macaroons"
 )
 
@@ -30,4 +31,8 @@ type Config struct {
 	// job of the signer RPC server is simply to proxy valid requests to
 	// the active signer instance.
 	Signer input.Signer
+
+	// KeyRing is an interface that the signer will use to derive any keys
+	// for signing messages.
+	KeyRing keychain.SecretKeyRing
 }

lnrpc/signrpc/signer.pb.go

@@ -472,6 +472,194 @@ func (m *InputScriptResp) GetInputScripts() []*InputScript {
 	return nil
 }
 
+type SignMessageReq struct {
+	/// The message to be signed.
+	Msg []byte `protobuf:"bytes,1,opt,name=msg,proto3" json:"msg,omitempty"`
+	/// The key locator that identifies which key to use for signing.
+	KeyLoc               *KeyLocator `protobuf:"bytes,2,opt,name=key_loc,json=keyLoc,proto3" json:"key_loc,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}    `json:"-"`
+	XXX_unrecognized     []byte      `json:"-"`
+	XXX_sizecache        int32       `json:"-"`
+}
+
+func (m *SignMessageReq) Reset()         { *m = SignMessageReq{} }
+func (m *SignMessageReq) String() string { return proto.CompactTextString(m) }
+func (*SignMessageReq) ProtoMessage()    {}
+func (*SignMessageReq) Descriptor() ([]byte, []int) {
+	return fileDescriptor_4ecd772f6c7ffacf, []int{8}
+}
+
+func (m *SignMessageReq) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_SignMessageReq.Unmarshal(m, b)
+}
+func (m *SignMessageReq) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_SignMessageReq.Marshal(b, m, deterministic)
+}
+func (m *SignMessageReq) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_SignMessageReq.Merge(m, src)
+}
+func (m *SignMessageReq) XXX_Size() int {
+	return xxx_messageInfo_SignMessageReq.Size(m)
+}
+func (m *SignMessageReq) XXX_DiscardUnknown() {
+	xxx_messageInfo_SignMessageReq.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_SignMessageReq proto.InternalMessageInfo
+
+func (m *SignMessageReq) GetMsg() []byte {
+	if m != nil {
+		return m.Msg
+	}
+	return nil
+}
+
+func (m *SignMessageReq) GetKeyLoc() *KeyLocator {
+	if m != nil {
+		return m.KeyLoc
+	}
+	return nil
+}
+
+type SignMessageResp struct {
+	//*
+	//The signature for the given message in the DER format.
+	Signature            []byte   `protobuf:"bytes,1,opt,name=signature,proto3" json:"signature,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *SignMessageResp) Reset()         { *m = SignMessageResp{} }
+func (m *SignMessageResp) String() string { return proto.CompactTextString(m) }
+func (*SignMessageResp) ProtoMessage()    {}
+func (*SignMessageResp) Descriptor() ([]byte, []int) {
+	return fileDescriptor_4ecd772f6c7ffacf, []int{9}
+}
+
+func (m *SignMessageResp) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_SignMessageResp.Unmarshal(m, b)
+}
+func (m *SignMessageResp) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_SignMessageResp.Marshal(b, m, deterministic)
+}
+func (m *SignMessageResp) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_SignMessageResp.Merge(m, src)
+}
+func (m *SignMessageResp) XXX_Size() int {
+	return xxx_messageInfo_SignMessageResp.Size(m)
+}
+func (m *SignMessageResp) XXX_DiscardUnknown() {
+	xxx_messageInfo_SignMessageResp.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_SignMessageResp proto.InternalMessageInfo
+
+func (m *SignMessageResp) GetSignature() []byte {
+	if m != nil {
+		return m.Signature
+	}
+	return nil
+}
+
+type VerifyMessageReq struct {
+	/// The message over which the signature is to be verified.
+	Msg []byte `protobuf:"bytes,1,opt,name=msg,proto3" json:"msg,omitempty"`
+	/// The DER encoded signature to be verified over the given message.
+	Signature []byte `protobuf:"bytes,2,opt,name=signature,proto3" json:"signature,omitempty"`
+	/// The public key the signature has to be valid for.
+	Pubkey               []byte   `protobuf:"bytes,3,opt,name=pubkey,proto3" json:"pubkey,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *VerifyMessageReq) Reset()         { *m = VerifyMessageReq{} }
+func (m *VerifyMessageReq) String() string { return proto.CompactTextString(m) }
+func (*VerifyMessageReq) ProtoMessage()    {}
+func (*VerifyMessageReq) Descriptor() ([]byte, []int) {
+	return fileDescriptor_4ecd772f6c7ffacf, []int{10}
+}
+
+func (m *VerifyMessageReq) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_VerifyMessageReq.Unmarshal(m, b)
+}
+func (m *VerifyMessageReq) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_VerifyMessageReq.Marshal(b, m, deterministic)
+}
+func (m *VerifyMessageReq) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_VerifyMessageReq.Merge(m, src)
+}
+func (m *VerifyMessageReq) XXX_Size() int {
+	return xxx_messageInfo_VerifyMessageReq.Size(m)
+}
+func (m *VerifyMessageReq) XXX_DiscardUnknown() {
+	xxx_messageInfo_VerifyMessageReq.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_VerifyMessageReq proto.InternalMessageInfo
+
+func (m *VerifyMessageReq) GetMsg() []byte {
+	if m != nil {
+		return m.Msg
+	}
+	return nil
+}
+
+func (m *VerifyMessageReq) GetSignature() []byte {
+	if m != nil {
+		return m.Signature
+	}
+	return nil
+}
+
+func (m *VerifyMessageReq) GetPubkey() []byte {
+	if m != nil {
+		return m.Pubkey
+	}
+	return nil
+}
+
+type VerifyMessageResp struct {
+	/// Whether the signature was valid over the given message.
+	Valid                bool     `protobuf:"varint,1,opt,name=valid,proto3" json:"valid,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
+}
+
+func (m *VerifyMessageResp) Reset()         { *m = VerifyMessageResp{} }
+func (m *VerifyMessageResp) String() string { return proto.CompactTextString(m) }
+func (*VerifyMessageResp) ProtoMessage()    {}
+func (*VerifyMessageResp) Descriptor() ([]byte, []int) {
+	return fileDescriptor_4ecd772f6c7ffacf, []int{11}
+}
+
+func (m *VerifyMessageResp) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_VerifyMessageResp.Unmarshal(m, b)
+}
+func (m *VerifyMessageResp) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_VerifyMessageResp.Marshal(b, m, deterministic)
+}
+func (m *VerifyMessageResp) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_VerifyMessageResp.Merge(m, src)
+}
+func (m *VerifyMessageResp) XXX_Size() int {
+	return xxx_messageInfo_VerifyMessageResp.Size(m)
+}
+func (m *VerifyMessageResp) XXX_DiscardUnknown() {
+	xxx_messageInfo_VerifyMessageResp.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_VerifyMessageResp proto.InternalMessageInfo
+
+func (m *VerifyMessageResp) GetValid() bool {
+	if m != nil {
+		return m.Valid
+	}
+	return false
+}
+
 func init() {
 	proto.RegisterType((*KeyLocator)(nil), "signrpc.KeyLocator")
 	proto.RegisterType((*KeyDescriptor)(nil), "signrpc.KeyDescriptor")
@@ -481,48 +669,59 @@ func init() {
 	proto.RegisterType((*SignResp)(nil), "signrpc.SignResp")
 	proto.RegisterType((*InputScript)(nil), "signrpc.InputScript")
 	proto.RegisterType((*InputScriptResp)(nil), "signrpc.InputScriptResp")
+	proto.RegisterType((*SignMessageReq)(nil), "signrpc.SignMessageReq")
+	proto.RegisterType((*SignMessageResp)(nil), "signrpc.SignMessageResp")
+	proto.RegisterType((*VerifyMessageReq)(nil), "signrpc.VerifyMessageReq")
+	proto.RegisterType((*VerifyMessageResp)(nil), "signrpc.VerifyMessageResp")
 }
 
 func init() { proto.RegisterFile("signrpc/signer.proto", fileDescriptor_4ecd772f6c7ffacf) }
 
 var fileDescriptor_4ecd772f6c7ffacf = []byte{
-	// 562 bytes of a gzipped FileDescriptorProto
+	// 676 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x6c, 0x53, 0x4f, 0x8f, 0xd3, 0x3e,
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x94, 0x54, 0xcb, 0x6e, 0xd3, 0x40,
-	0x10, 0x55, 0xb7, 0xbf, 0x36, 0xdd, 0x49, 0xd2, 0x1f, 0x98, 0x0a, 0x02, 0x08, 0x51, 0x22, 0x2d,
+	0x14, 0x55, 0x13, 0xf2, 0xe8, 0x75, 0xdc, 0xc7, 0x50, 0x15, 0xb7, 0x80, 0x08, 0x96, 0x8a, 0x82,
-	0xea, 0x01, 0x5a, 0x51, 0x10, 0x12, 0x9c, 0xd0, 0x82, 0x56, 0xac, 0xba, 0xd2, 0x4a, 0x6e, 0x4f,
+	0x04, 0x89, 0x08, 0x08, 0x09, 0x56, 0xa8, 0xa0, 0x8a, 0xaa, 0x45, 0x45, 0x93, 0x8a, 0x45, 0x37,
-	0x5c, 0xa2, 0x34, 0x35, 0xa9, 0x95, 0x34, 0xf1, 0xc6, 0x0e, 0x69, 0x6e, 0x7c, 0x07, 0xbe, 0x30,
+	0x91, 0xe3, 0x4c, 0x9d, 0x91, 0x1d, 0x7b, 0xea, 0x19, 0xe3, 0xf8, 0x17, 0xd8, 0xf2, 0xc3, 0x68,
-	0x1a, 0x3b, 0xfd, 0x07, 0x9c, 0x9a, 0xf7, 0x3c, 0x33, 0xef, 0x79, 0x5e, 0x0d, 0x03, 0xc9, 0xe3,
+	0x1e, 0x49, 0xec, 0xf0, 0x90, 0x58, 0xc5, 0xe7, 0xce, 0x9d, 0x73, 0x8f, 0xcf, 0xb9, 0x31, 0x1c,
-	0xac, 0x10, 0xd1, 0x04, 0x7f, 0x59, 0x31, 0x16, 0x45, 0xae, 0x72, 0x62, 0x35, 0xac, 0xff, 0x15,
+	0x70, 0x1a, 0xc4, 0x29, 0xf3, 0x07, 0xf2, 0x97, 0xa4, 0x7d, 0x96, 0x26, 0x22, 0x41, 0x2d, 0x53,
-	0x60, 0xc6, 0xea, 0x9b, 0x3c, 0x0a, 0x55, 0x5e, 0x90, 0x67, 0x00, 0x09, 0xab, 0x83, 0xef, 0xe1,
+	0x75, 0x3f, 0x03, 0x5c, 0x90, 0xe2, 0x32, 0xf1, 0x3d, 0x91, 0xa4, 0xe8, 0x31, 0x40, 0x48, 0x8a,
-	0x86, 0xa7, 0xb5, 0xd7, 0x1a, 0xb6, 0x46, 0x1d, 0x7a, 0x9e, 0xb0, 0xfa, 0x4a, 0x13, 0xe4, 0x29,
+	0xf1, 0xad, 0x37, 0xa7, 0x51, 0xe1, 0x6c, 0x75, 0xb7, 0x7a, 0x0d, 0xbc, 0x1d, 0x92, 0xe2, 0x4c,
-	0x20, 0x08, 0x78, 0xb6, 0x62, 0x5b, 0xef, 0x4c, 0x9f, 0xf6, 0x12, 0x56, 0x5f, 0x23, 0xf6, 0x43,
+	0x15, 0xd0, 0x43, 0x90, 0x60, 0x4c, 0xe3, 0x29, 0x59, 0x38, 0x35, 0x75, 0xda, 0x0e, 0x49, 0x71,
-	0x70, 0x67, 0xac, 0xfe, 0xc2, 0x64, 0x54, 0x70, 0x81, 0xc3, 0x7c, 0x70, 0x8b, 0xb0, 0x0a, 0xb0,
+	0x2e, 0xb1, 0xeb, 0x81, 0x7d, 0x41, 0x8a, 0x4f, 0x84, 0xfb, 0x29, 0x65, 0x92, 0xcc, 0x05, 0x3b,
-	0x63, 0x59, 0x2b, 0x26, 0xf5, 0x3c, 0x87, 0xda, 0x45, 0x58, 0xcd, 0x58, 0x7d, 0x89, 0x14, 0x79,
+	0xf5, 0xf2, 0xb1, 0xbc, 0x31, 0x29, 0x04, 0xe1, 0x8a, 0xaf, 0x83, 0xad, 0xd4, 0xcb, 0x2f, 0x48,
-	0x05, 0x16, 0x9e, 0xa7, 0x79, 0xa4, 0xe7, 0xd9, 0xd3, 0x07, 0xe3, 0xc6, 0xd9, 0xf8, 0x60, 0x8b,
+	0x71, 0x2a, 0x4b, 0xe8, 0x05, 0xb4, 0xe4, 0x79, 0x94, 0xf8, 0x8a, 0xcf, 0x1a, 0xde, 0xef, 0x1b,
-	0x76, 0x13, 0xfd, 0xed, 0x7f, 0x84, 0xce, 0x62, 0x7b, 0x5b, 0x2a, 0x32, 0x80, 0xce, 0x8f, 0x30,
+	0x65, 0xfd, 0xb5, 0x2c, 0xdc, 0x0c, 0xd5, 0xb3, 0xfb, 0x1e, 0x1a, 0xd7, 0x8b, 0xab, 0x4c, 0xa0,
-	0x2d, 0x99, 0x1e, 0xd9, 0xa6, 0x06, 0xa0, 0x3d, 0x91, 0x04, 0x46, 0x5f, 0x8f, 0x73, 0x68, 0x4f,
+	0x03, 0x68, 0x7c, 0xf7, 0xa2, 0x8c, 0x28, 0xca, 0x3a, 0xd6, 0x40, 0xca, 0x63, 0xe1, 0x58, 0xcf,
-	0x24, 0x73, 0x8d, 0xfd, 0x5f, 0x67, 0xd0, 0x9f, 0xf3, 0x38, 0x3b, 0x32, 0xf8, 0x06, 0xd0, 0x7d,
+	0x57, 0x74, 0x1d, 0xdc, 0x66, 0xe1, 0x48, 0x61, 0xf7, 0x67, 0x0d, 0x76, 0x46, 0x34, 0x88, 0x4b,
-	0xb0, 0x62, 0x32, 0xd2, 0x83, 0xec, 0xe9, 0xc3, 0x63, 0xf5, 0x43, 0x25, 0x45, 0x93, 0x08, 0xc9,
+	0x02, 0x5f, 0x81, 0x54, 0x3f, 0x9e, 0x12, 0xee, 0x2b, 0x22, 0x6b, 0x78, 0x58, 0x9e, 0xbe, 0xee,
-	0x0b, 0x70, 0x24, 0xcf, 0xe2, 0x94, 0x05, 0xaa, 0x62, 0x61, 0xd2, 0xa8, 0xd8, 0x86, 0x5b, 0x20,
+	0xc4, 0x52, 0xa4, 0x84, 0xe8, 0x29, 0x74, 0x38, 0x8d, 0x83, 0x88, 0x8c, 0x45, 0x4e, 0xbc, 0xd0,
-	0x85, 0x25, 0xab, 0xbc, 0x5c, 0xee, 0x4b, 0xda, 0xa6, 0xc4, 0x70, 0xa6, 0xe4, 0x02, 0xfa, 0x15,
+	0x4c, 0xb1, 0x74, 0xed, 0x5a, 0x96, 0x64, 0xcb, 0x34, 0xc9, 0x26, 0xab, 0x96, 0xba, 0x6e, 0xd1,
-	0x57, 0x19, 0x93, 0x72, 0xe7, 0xf6, 0x3f, 0x5d, 0xe4, 0x36, 0xac, 0xb1, 0x4c, 0x5e, 0x42, 0x37,
+	0x35, 0xdd, 0x72, 0x02, 0x3b, 0x39, 0x15, 0x31, 0xe1, 0x7c, 0xa9, 0xf6, 0x9e, 0x6a, 0xb2, 0x4d,
-	0x2f, 0x95, 0x28, 0x95, 0xd7, 0xd1, 0xee, 0xfa, 0x7b, 0x77, 0x7a, 0x0b, 0xb4, 0x39, 0x25, 0x1e,
+	0x55, 0x4b, 0x46, 0xcf, 0xa0, 0x99, 0x64, 0x82, 0x65, 0xc2, 0x69, 0x28, 0x75, 0x3b, 0x2b, 0x75,
-	0x60, 0x9c, 0xeb, 0x50, 0xae, 0x3d, 0x6b, 0xd8, 0x1a, 0xb9, 0x74, 0x07, 0xc9, 0x73, 0xb0, 0x79,
+	0xca, 0x05, 0x6c, 0x4e, 0x91, 0x03, 0x32, 0xce, 0x99, 0xc7, 0x67, 0x4e, 0xab, 0xbb, 0xd5, 0xb3,
-	0x26, 0x4a, 0xd5, 0x44, 0xd6, 0xd3, 0x91, 0x81, 0xa6, 0x4c, 0x68, 0x11, 0x58, 0xb8, 0x14, 0xca,
+	0xf1, 0x12, 0xa2, 0x27, 0x60, 0xd1, 0x98, 0x65, 0xc2, 0x44, 0xd6, 0x56, 0x91, 0x81, 0x2a, 0xe9,
-	0xee, 0xc8, 0x10, 0x1c, 0x8c, 0x4b, 0x6d, 0x4f, 0xd2, 0x82, 0x22, 0xac, 0x16, 0x5b, 0x13, 0xd6,
+	0xd0, 0x7c, 0x68, 0x49, 0x53, 0x30, 0xb9, 0x43, 0x5d, 0xe8, 0xc8, 0xb8, 0xc4, 0xa2, 0x92, 0x16,
-	0x7b, 0x00, 0x34, 0xa0, 0x17, 0x26, 0xbd, 0xb3, 0x61, 0x7b, 0x64, 0x4f, 0x1f, 0xed, 0x3d, 0x9d,
+	0xa4, 0x5e, 0x7e, 0xbd, 0xd0, 0x61, 0xbd, 0x05, 0x90, 0x02, 0x94, 0x61, 0xdc, 0xa9, 0x75, 0xeb,
-	0x2e, 0x97, 0x9e, 0xcb, 0x06, 0x4b, 0xff, 0x02, 0x7a, 0x46, 0x44, 0x0a, 0xf2, 0x18, 0x7a, 0xa8,
+	0x3d, 0x6b, 0xf8, 0x60, 0xa5, 0xa9, 0x6a, 0x2e, 0xde, 0xe6, 0x06, 0x73, 0xf7, 0x04, 0xda, 0x7a,
-	0x22, 0x79, 0x8c, 0x0a, 0xed, 0x91, 0x43, 0xad, 0x22, 0xac, 0xe6, 0x3c, 0x96, 0xfe, 0x15, 0xd8,
+	0x08, 0x67, 0xe8, 0x08, 0xda, 0x72, 0x0a, 0xa7, 0x81, 0x9c, 0x50, 0xef, 0x75, 0x70, 0x2b, 0xf5,
-	0xd7, 0xe8, 0xac, 0xb9, 0xbd, 0x07, 0x56, 0xb3, 0x8e, 0x5d, 0x61, 0x03, 0xf1, 0x5f, 0x2a, 0x79,
+	0xf2, 0x11, 0x0d, 0xb8, 0x7b, 0x06, 0xd6, 0xb9, 0x54, 0x66, 0xde, 0xde, 0x81, 0x96, 0xb1, 0x63,
-	0x7c, 0x1a, 0x34, 0xca, 0x35, 0x49, 0xdf, 0xc0, 0xff, 0x47, 0x73, 0xb4, 0xea, 0x07, 0x70, 0xcd,
+	0xd9, 0x68, 0xa0, 0xdc, 0x52, 0x4e, 0x83, 0x6a, 0xd0, 0x72, 0x9c, 0x49, 0xfa, 0x12, 0x76, 0x4b,
-	0x1e, 0x4c, 0x8f, 0x99, 0x68, 0x4f, 0x07, 0x7b, 0xf3, 0xc7, 0x0d, 0x0e, 0x3f, 0x00, 0x39, 0xfd,
+	0x3c, 0x6a, 0xea, 0x3b, 0xb0, 0xb5, 0x0f, 0xfa, 0x8e, 0x66, 0xb4, 0x86, 0x07, 0x2b, 0xf1, 0xe5,
-	0xd9, 0x82, 0xee, 0x5c, 0x3f, 0x1d, 0xf2, 0x0e, 0x5c, 0xfc, 0xba, 0xd5, 0x5b, 0xa7, 0x61, 0x45,
+	0x0b, 0x1d, 0xba, 0x06, 0xdc, 0xfd, 0xaa, 0xd7, 0xe6, 0x0b, 0xe1, 0xdc, 0x0b, 0x88, 0x34, 0x6a,
-	0xee, 0x9d, 0x5c, 0x9e, 0xb2, 0xbb, 0x27, 0xf7, 0xff, 0x60, 0xa4, 0x20, 0x9f, 0x80, 0x7c, 0xce,
+	0x0f, 0xea, 0x73, 0x1e, 0x18, 0x7f, 0xe4, 0xe3, 0x7f, 0x6e, 0xf1, 0x00, 0x76, 0x2b, 0x8c, 0x9c,
-	0x37, 0xa2, 0x54, 0xec, 0xf8, 0x76, 0x7f, 0xb7, 0x7a, 0xff, 0x34, 0xc3, 0xa4, 0xb8, 0x9c, 0x7c,
+	0xa1, 0x47, 0xa0, 0xec, 0xf2, 0x44, 0x96, 0x12, 0x43, 0xbc, 0x2e, 0xb8, 0x37, 0xb0, 0xf7, 0x8d,
-	0x7b, 0x1d, 0x73, 0xb5, 0x2e, 0x97, 0xe3, 0x28, 0xdf, 0x4c, 0x52, 0x1e, 0xaf, 0x55, 0xc6, 0xb3,
+	0xa4, 0xf4, 0xb6, 0xf8, 0xa7, 0x88, 0x0a, 0x47, 0x6d, 0x83, 0x03, 0x1d, 0x42, 0x93, 0x65, 0x93,
-	0x38, 0x63, 0xaa, 0xca, 0x8b, 0x64, 0x92, 0x66, 0xab, 0x49, 0xba, 0x7f, 0xe2, 0x85, 0x88, 0x96,
+	0x90, 0x14, 0x66, 0x1f, 0x0d, 0x72, 0x9f, 0xc3, 0xfe, 0x06, 0x37, 0x67, 0xe6, 0xef, 0x45, 0xa7,
-	0x5d, 0xfd, 0xc8, 0xdf, 0xfe, 0x0e, 0x00, 0x00, 0xff, 0xff, 0x80, 0x01, 0xce, 0xe1, 0xfc, 0x03,
+	0x8a, 0xbe, 0x8d, 0x35, 0x18, 0xfe, 0xa8, 0x41, 0x73, 0xa4, 0x3e, 0x22, 0xe8, 0x0d, 0xd8, 0xf2,
-	0x00, 0x00,
+	0xe9, 0x4a, 0xed, 0x1f, 0xf6, 0x72, 0xb4, 0x57, 0x59, 0x03, 0x4c, 0xee, 0x8e, 0xf7, 0x37, 0x2a,
+	0x9c, 0xa1, 0x0f, 0x80, 0x3e, 0x26, 0x73, 0x96, 0x09, 0x52, 0xce, 0xf9, 0xf7, 0xab, 0xce, 0x1f,
+	0x63, 0xd1, 0x0c, 0x56, 0xc9, 0x3a, 0x54, 0x5d, 0xbe, 0xb5, 0x3b, 0x25, 0x86, 0x4d, 0xa7, 0xcf,
+	0xc0, 0xae, 0xbc, 0x2f, 0x3a, 0x5a, 0xb5, 0x6e, 0x7a, 0x7c, 0x7c, 0xfc, 0xb7, 0x23, 0xce, 0x4e,
+	0x07, 0x37, 0x2f, 0x03, 0x2a, 0x66, 0xd9, 0xa4, 0xef, 0x27, 0xf3, 0x41, 0x44, 0x83, 0x99, 0x88,
+	0x69, 0x1c, 0xc4, 0x44, 0xe4, 0x49, 0x1a, 0x0e, 0xa2, 0x78, 0x3a, 0x88, 0x56, 0x9f, 0xdd, 0x94,
+	0xf9, 0x93, 0xa6, 0xfa, 0xf0, 0xbe, 0xfe, 0x15, 0x00, 0x00, 0xff, 0xff, 0x09, 0xde, 0xe5, 0x7f,
+	0x90, 0x05, 0x00, 0x00,
 }
 
 // Reference imports to suppress errors if they are not otherwise used.
@@ -559,6 +758,20 @@ type SignerClient interface {
 	//in the TxOut field, the value in that same field, and finally the input
 	//index.
 	ComputeInputScript(ctx context.Context, in *SignReq, opts ...grpc.CallOption) (*InputScriptResp, error)
+	//*
+	//SignMessage signs a message with the key specified in the key locator. The
+	//returned signature is DER encoded.
+	//
+	//The main difference to SignMessage in the main RPC is that a specific key is
+	//used to sign the message instead of the node identity private key.
+	SignMessage(ctx context.Context, in *SignMessageReq, opts ...grpc.CallOption) (*SignMessageResp, error)
+	//*
+	//VerifyMessage verifies a signature over a message using the public key
+	//provided. The signature must be DER encoded.
+	//
+	//The main difference to VerifyMessage in the main RPC is that the public key
+	//used to sign the message does not have to be a node known to the network.
+	VerifyMessage(ctx context.Context, in *VerifyMessageReq, opts ...grpc.CallOption) (*VerifyMessageResp, error)
 }
 
 type signerClient struct {
@@ -587,6 +800,24 @@ func (c *signerClient) ComputeInputScript(ctx context.Context, in *SignReq, opts
 	return out, nil
 }
 
+func (c *signerClient) SignMessage(ctx context.Context, in *SignMessageReq, opts ...grpc.CallOption) (*SignMessageResp, error) {
+	out := new(SignMessageResp)
+	err := c.cc.Invoke(ctx, "/signrpc.Signer/SignMessage", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *signerClient) VerifyMessage(ctx context.Context, in *VerifyMessageReq, opts ...grpc.CallOption) (*VerifyMessageResp, error) {
+	out := new(VerifyMessageResp)
+	err := c.cc.Invoke(ctx, "/signrpc.Signer/VerifyMessage", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
 // SignerServer is the server API for Signer service.
 type SignerServer interface {
 	//*
@@ -611,6 +842,20 @@ type SignerServer interface {
 	//in the TxOut field, the value in that same field, and finally the input
 	//index.
 	ComputeInputScript(context.Context, *SignReq) (*InputScriptResp, error)
+	//*
+	//SignMessage signs a message with the key specified in the key locator. The
+	//returned signature is DER encoded.
+	//
+	//The main difference to SignMessage in the main RPC is that a specific key is
+	//used to sign the message instead of the node identity private key.
+	SignMessage(context.Context, *SignMessageReq) (*SignMessageResp, error)
+	//*
+	//VerifyMessage verifies a signature over a message using the public key
+	//provided. The signature must be DER encoded.
+	//
+	//The main difference to VerifyMessage in the main RPC is that the public key
+	//used to sign the message does not have to be a node known to the network.
+	VerifyMessage(context.Context, *VerifyMessageReq) (*VerifyMessageResp, error)
 }
 
 func RegisterSignerServer(s *grpc.Server, srv SignerServer) {
@@ -653,6 +898,42 @@ func _Signer_ComputeInputScript_Handler(srv interface{}, ctx context.Context, de
 	return interceptor(ctx, in, info, handler)
 }
 
+func _Signer_SignMessage_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(SignMessageReq)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(SignerServer).SignMessage(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/signrpc.Signer/SignMessage",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(SignerServer).SignMessage(ctx, req.(*SignMessageReq))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _Signer_VerifyMessage_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(VerifyMessageReq)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(SignerServer).VerifyMessage(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/signrpc.Signer/VerifyMessage",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(SignerServer).VerifyMessage(ctx, req.(*VerifyMessageReq))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
 var _Signer_serviceDesc = grpc.ServiceDesc{
 	ServiceName: "signrpc.Signer",
 	HandlerType: (*SignerServer)(nil),
@@ -665,6 +946,14 @@ var _Signer_serviceDesc = grpc.ServiceDesc{
 			MethodName: "ComputeInputScript",
 			Handler:    _Signer_ComputeInputScript_Handler,
 		},
+		{
+			MethodName: "SignMessage",
+			Handler:    _Signer_SignMessage_Handler,
+		},
+		{
+			MethodName: "VerifyMessage",
+			Handler:    _Signer_VerifyMessage_Handler,
+		},
 	},
 	Streams:  []grpc.StreamDesc{},
 	Metadata: "signrpc/signer.proto",

lnrpc/signrpc/signer.proto

@@ -13,17 +13,17 @@ message KeyLocator {
 }
 
 message KeyDescriptor {
-     /**
+    /**
-     The raw bytes of the key being identified. Either this or the KeyLocator
+    The raw bytes of the key being identified. Either this or the KeyLocator
-     must be specified.
+    must be specified.
-     */
+    */
-     bytes raw_key_bytes = 1;
+    bytes raw_key_bytes = 1;
 
-     /** 
+    /** 
-     The key locator that identifies which key to use for signing. Either this
+    The key locator that identifies which key to use for signing. Either this
-     or the raw bytes of the target key must be specified.
+    or the raw bytes of the target key must be specified.
-     */
+    */
-     KeyLocator key_loc = 2;
+    KeyLocator key_loc = 2;
 }
 
 message TxOut {
@@ -119,6 +119,38 @@ message InputScriptResp {
     repeated InputScript input_scripts = 1;
 }
 
+message SignMessageReq {
+    /// The message to be signed.
+    bytes msg = 1;
+
+    /// The key locator that identifies which key to use for signing.
+    KeyLocator key_loc = 2;
+}
+message SignMessageResp {
+    /**
+    The signature for the given message in the fixed-size LN wire format.
+    */
+    bytes signature = 1;
+}
+
+message VerifyMessageReq {
+    /// The message over which the signature is to be verified.
+    bytes msg = 1;
+
+    /**
+    The fixed-size LN wire encoded signature to be verified over the given
+    message.
+    */
+    bytes signature = 2;
+
+    /// The public key the signature has to be valid for.
+    bytes pubkey = 3;
+}
+message VerifyMessageResp {
+    /// Whether the signature was valid over the given message.
+    bool valid = 1;
+}
+
 service Signer {
     /**
     SignOutputRaw is a method that can be used to generated a signature for a
@@ -130,7 +162,7 @@ service Signer {
     If we are  unable to sign using the specified keys, then an error will be
     returned.
     */
-    rpc SignOutputRaw(SignReq) returns (SignResp);
+    rpc SignOutputRaw (SignReq) returns (SignResp);
 
     /**
     ComputeInputScript generates a complete InputIndex for the passed
@@ -144,5 +176,23 @@ service Signer {
     in the TxOut field, the value in that same field, and finally the input
     index.
     */
-    rpc ComputeInputScript(SignReq) returns (InputScriptResp); 
+    rpc ComputeInputScript (SignReq) returns (InputScriptResp);
+
+    /**
+    SignMessage signs a message with the key specified in the key locator. The
+    returned signature is fixed-size LN wire format encoded.
+    
+    The main difference to SignMessage in the main RPC is that a specific key is
+    used to sign the message instead of the node identity private key.
+    */
+    rpc SignMessage (SignMessageReq) returns (SignMessageResp);
+
+    /**
+    VerifyMessage verifies a signature over a message using the public key
+    provided. The signature must be fixed-size LN wire format encoded.
+    
+    The main difference to VerifyMessage in the main RPC is that the public key
+    used to sign the message does not have to be a node known to the network.
+    */
+    rpc VerifyMessage (VerifyMessageReq) returns (VerifyMessageResp);
 }

lnrpc/signrpc/signer_server.go

@@ -11,12 +11,13 @@ import (
 	"path/filepath"
 
 	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	"github.com/btcsuite/btcd/txscript"
 	"github.com/btcsuite/btcd/wire"
 	"github.com/lightningnetwork/lnd/input"
 	"github.com/lightningnetwork/lnd/keychain"
 	"github.com/lightningnetwork/lnd/lnrpc"
-
+	"github.com/lightningnetwork/lnd/lnwire"
 	"google.golang.org/grpc"
 	"gopkg.in/macaroon-bakery.v2/bakery"
 )
@@ -37,6 +38,10 @@ var (
 			Entity: "signer",
 			Action: "generate",
 		},
+		{
+			Entity: "signer",
+			Action: "read",
+		},
 	}
 
 	// macPermissions maps RPC calls to the permissions they require.
@@ -49,6 +54,14 @@ var (
 			Entity: "signer",
 			Action: "generate",
 		}},
+		"/signrpc.Signer/SignMessage": {{
+			Entity: "signer",
+			Action: "generate",
+		}},
+		"/signrpc.Signer/VerifyMessage": {{
+			Entity: "signer",
+			Action: "read",
+		}},
 	}
 
 	// DefaultSignerMacFilename is the default name of the signer macaroon
@@ -383,3 +396,84 @@ func (s *Server) ComputeInputScript(ctx context.Context,
 
 	return resp, nil
 }
+
+// SignMessage signs a message with the key specified in the key locator. The
+// returned signature is fixed-size LN wire format encoded.
+func (s *Server) SignMessage(ctx context.Context,
+	in *SignMessageReq) (*SignMessageResp, error) {
+
+	if in.Msg == nil {
+		return nil, fmt.Errorf("a message to sign MUST be passed in")
+	}
+	if in.KeyLoc == nil {
+		return nil, fmt.Errorf("a key locator MUST be passed in")
+	}
+
+	// Derive the private key we'll be using for signing.
+	keyLocator := keychain.KeyLocator{
+		Family: keychain.KeyFamily(in.KeyLoc.KeyFamily),
+		Index:  uint32(in.KeyLoc.KeyIndex),
+	}
+	privKey, err := s.cfg.KeyRing.DerivePrivKey(keychain.KeyDescriptor{
+		KeyLocator: keyLocator,
+	})
+	if err != nil {
+		return nil, fmt.Errorf("can't derive private key: %v", err)
+	}
+
+	// The signature is over the sha256 hash of the message.
+	digest := chainhash.HashB(in.Msg)
+
+	// Create the raw ECDSA signature first and convert it to the final wire
+	// format after.
+	sig, err := privKey.Sign(digest)
+	if err != nil {
+		return nil, fmt.Errorf("can't sign the hash: %v", err)
+	}
+	wireSig, err := lnwire.NewSigFromSignature(sig)
+	if err != nil {
+		return nil, fmt.Errorf("can't convert to wire format: %v", err)
+	}
+	return &SignMessageResp{
+		Signature: wireSig.ToSignatureBytes(),
+	}, nil
+}
+
+// VerifyMessage verifies a signature over a message using the public key
+// provided. The signature must be fixed-size LN wire format encoded.
+func (s *Server) VerifyMessage(ctx context.Context,
+	in *VerifyMessageReq) (*VerifyMessageResp, error) {
+
+	if in.Msg == nil {
+		return nil, fmt.Errorf("a message to verify MUST be passed in")
+	}
+	if in.Signature == nil {
+		return nil, fmt.Errorf("a signature to verify MUST be passed " +
+			"in")
+	}
+	if in.Pubkey == nil {
+		return nil, fmt.Errorf("a pubkey to verify MUST be passed in")
+	}
+	pubkey, err := btcec.ParsePubKey(in.Pubkey, btcec.S256())
+	if err != nil {
+		return nil, fmt.Errorf("unable to parse pubkey: %v", err)
+	}
+
+	// The signature must be fixed-size LN wire format encoded.
+	wireSig, err := lnwire.NewSigFromRawSignature(in.Signature)
+	if err != nil {
+		return nil, fmt.Errorf("failed to decode signature: %v", err)
+	}
+	sig, err := wireSig.ToSignature()
+	if err != nil {
+		return nil, fmt.Errorf("failed to convert from wire format: %v",
+			err)
+	}
+
+	// The signature is over the sha256 hash of the message.
+	digest := chainhash.HashB(in.Msg)
+	valid := sig.Verify(digest, pubkey)
+	return &VerifyMessageResp{
+		Valid: valid,
+	}, nil
+}

rpcserver.go

@@ -116,6 +116,10 @@ var (
 			Entity: "invoices",
 			Action: "read",
 		},
+		{
+			Entity: "signer",
+			Action: "read",
+		},
 	}
 
 	// writePermissions is a slice of all entities that allow write

subrpcserver_config.go

@@ -132,6 +132,9 @@ func (s *subRPCServerConfigs) PopulateDependencies(cc *chainControl,
 			subCfgValue.FieldByName("Signer").Set(
 				reflect.ValueOf(cc.signer),
 			)
+			subCfgValue.FieldByName("KeyRing").Set(
+				reflect.ValueOf(cc.keyRing),
+			)
 
 		case *walletrpc.Config:
 			subCfgValue := extractReflectValue(subCfg)