multi: add version to MuSig2 API, bump btcd/btcec to v2.3.2

With this commit we bump the github.com/btcd/btcec/v2 library to v2.3.2
which implements the MuSig2 BIP version v1.0.0rc2. With this the
github.com/btcsuite/btcd/btcec/v2/schnorr/musig2 package becomes
v1.0.0rc2 and the github.com/lightningnetwork/lnd/internal/musig2v040
stays at the old v0.4.0 version.

go.mod

@@ -4,7 +4,7 @@ require (
 	github.com/NebulousLabs/go-upnp v0.0.0-20180202185039-29b680b06c82
 	github.com/Yawning/aez v0.0.0-20211027044916-e49e68abd344
 	github.com/btcsuite/btcd v0.23.5-0.20230125025938-be056b0a0b2f
-	github.com/btcsuite/btcd/btcec/v2 v2.2.2
+	github.com/btcsuite/btcd/btcec/v2 v2.3.2
 	github.com/btcsuite/btcd/btcutil v1.1.3
 	github.com/btcsuite/btcd/btcutil/psbt v1.1.5
 	github.com/btcsuite/btcd/chaincfg/chainhash v1.0.2

go.sum

@@ -76,8 +76,9 @@ github.com/btcsuite/btcd v0.23.5-0.20230125025938-be056b0a0b2f/go.mod h1:0QJIIN1
 github.com/btcsuite/btcd/btcec/v2 v2.1.0/go.mod h1:2VzYrv4Gm4apmbVVsSq5bqf1Ec8v56E48Vt0Y/umPgA=
 github.com/btcsuite/btcd/btcec/v2 v2.1.1/go.mod h1:ctjw4H1kknNJmRN4iP1R7bTQ+v3GJkZBd6mui8ZsAZE=
 github.com/btcsuite/btcd/btcec/v2 v2.1.3/go.mod h1:ctjw4H1kknNJmRN4iP1R7bTQ+v3GJkZBd6mui8ZsAZE=
-github.com/btcsuite/btcd/btcec/v2 v2.2.2 h1:5uxe5YjoCq+JeOpg0gZSNHuFgeogrocBYxvg6w9sAgc=
 github.com/btcsuite/btcd/btcec/v2 v2.2.2/go.mod h1:9/CSmJxmuvqzX9Wh2fXMWToLOHhPd11lSPuIupwTkI8=
+github.com/btcsuite/btcd/btcec/v2 v2.3.2 h1:5n0X6hX0Zk+6omWcihdYvdAlGf2DfasC0GMf7DClJ3U=
+github.com/btcsuite/btcd/btcec/v2 v2.3.2/go.mod h1:zYzJ8etWJQIv1Ogk7OzpWjowwOdXY1W/17j2MW85J04=
 github.com/btcsuite/btcd/btcutil v1.0.0/go.mod h1:Uoxwv0pqYWhD//tfTiipkxNfdhG9UrLwaeswfjfdF0A=
 github.com/btcsuite/btcd/btcutil v1.1.0/go.mod h1:5OapHB7A2hBBWLm48mmw4MOHNJCcUBTwmWH/0Jn8VHE=
 github.com/btcsuite/btcd/btcutil v1.1.1/go.mod h1:nbKlBMNm9FGsdvKvu0essceubPiAcI57pYBNnsLAa34=
@@ -405,8 +406,6 @@ github.com/lightninglabs/protobuf-hex-display v1.4.3-hex-display h1:RZJ8H4ueU/aQ
 github.com/lightninglabs/protobuf-hex-display v1.4.3-hex-display/go.mod h1:2oKOBU042GKFHrdbgGiKax4xVrFiZu51lhacUZQ9MnE=
 github.com/lightningnetwork/lightning-onion v1.2.1-0.20221202012345-ca23184850a1 h1:Wm0g70gkcAu2pGpNZwfWPSVOY21j8IyYsNewwK4OkT4=
 github.com/lightningnetwork/lightning-onion v1.2.1-0.20221202012345-ca23184850a1/go.mod h1:7dDx73ApjEZA0kcknI799m2O5kkpfg4/gr7N092ojNo=
-github.com/lightningnetwork/lnd/cert v1.1.1 h1:Nsav0RlIDRbOnzz2Yu69SQlK939IKya3Q2S0mDviIN8=
-github.com/lightningnetwork/lnd/cert v1.1.1/go.mod h1:1P46svkkd73oSoeI4zjkVKgZNwGq8bkGuPR8z+5vQUs=
 github.com/lightningnetwork/lnd/cert v1.2.0 h1:IWfjHNMI5JgQZU5fdvDptF3DkVI38f4jO/s3tYgWFbE=
 github.com/lightningnetwork/lnd/cert v1.2.0/go.mod h1:04JhIEodoR6usBN5+XBRtLEEmEHsclLi0tEyxZQNP+w=
 github.com/lightningnetwork/lnd/clock v1.0.1/go.mod h1:KnQudQ6w0IAMZi1SgvecLZQZ43ra2vpDNj7H/aasemg=

input/musig2.go

@@ -8,9 +8,26 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcec/v2/schnorr"
 	"github.com/btcsuite/btcd/btcec/v2/schnorr/musig2"
+	"github.com/lightningnetwork/lnd/internal/musig2v040"
 	"github.com/lightningnetwork/lnd/keychain"
 )
 
+// MuSig2Version is a type that defines the different versions of the MuSig2
+// as defined in the BIP draft:
+// (https://github.com/jonasnick/bips/blob/musig2/bip-musig2.mediawiki)
+type MuSig2Version uint8
+
+const (
+	// MuSig2Version040 is version 0.4.0 of the MuSig2 BIP draft. This will
+	// use the lnd internal/musig2v040 package.
+	MuSig2Version040 MuSig2Version = 0
+
+	// MuSig2Version100RC2 is version 1.0.0rc2 of the MuSig2 BIP draft. This
+	// uses the github.com/btcsuite/btcd/btcec/v2/schnorr/musig2 package
+	// at git tag `btcec/v2.3.1`.
+	MuSig2Version100RC2 MuSig2Version = 1
+)
+
 const (
 	// MuSig2PartialSigSize is the size of a MuSig2 partial signature.
 	// Because a partial signature is just the s value, this corresponds to
@@ -31,9 +48,9 @@ type MuSig2Signer interface {
 	// public key of the local signing key. If nonces of other parties are
 	// already known, they can be submitted as well to reduce the number of
 	// method calls necessary later on.
-	MuSig2CreateSession(keychain.KeyLocator, []*btcec.PublicKey,
-		*MuSig2Tweaks, [][musig2.PubNonceSize]byte) (*MuSig2SessionInfo,
-		error)
+	MuSig2CreateSession(MuSig2Version, keychain.KeyLocator,
+		[]*btcec.PublicKey, *MuSig2Tweaks,
+		[][musig2.PubNonceSize]byte) (*MuSig2SessionInfo, error)
 
 	// MuSig2RegisterNonces registers one or more public nonces of other
 	// signing participants for a session identified by its ID. This method
@@ -117,6 +134,10 @@ type MuSig2SessionInfo struct {
 	// is the hash over the combined public key and the local public nonces.
 	SessionID [32]byte
 
+	// Version is the version of the MuSig2 BIP this signing session is
+	// using.
+	Version MuSig2Version
+
 	// PublicNonce contains the public nonce of the local signer session.
 	PublicNonce [musig2.PubNonceSize]byte
 
@@ -192,21 +213,71 @@ func (t *MuSig2Tweaks) ToContextOptions() []musig2.ContextOption {
 	return tweakOpts
 }
 
+// ToV040ContextOptions converts the tweak descriptor to v0.4.0 context options.
+func (t *MuSig2Tweaks) ToV040ContextOptions() []musig2v040.ContextOption {
+	var tweakOpts []musig2v040.ContextOption
+	if len(t.GenericTweaks) > 0 {
+		genericTweaksCopy := make(
+			[]musig2v040.KeyTweakDesc, len(t.GenericTweaks),
+		)
+		for idx := range t.GenericTweaks {
+			genericTweaksCopy[idx] = musig2v040.KeyTweakDesc{
+				Tweak:   t.GenericTweaks[idx].Tweak,
+				IsXOnly: t.GenericTweaks[idx].IsXOnly,
+			}
+		}
+		tweakOpts = append(tweakOpts, musig2v040.WithTweakedContext(
+			genericTweaksCopy...,
+		))
+	}
+
+	// The BIP0086 tweak and the taproot script tweak are mutually
+	// exclusive.
+	if t.TaprootBIP0086Tweak {
+		tweakOpts = append(tweakOpts, musig2v040.WithBip86TweakCtx())
+	} else if len(t.TaprootTweak) > 0 {
+		tweakOpts = append(tweakOpts, musig2v040.WithTaprootTweakCtx(
+			t.TaprootTweak,
+		))
+	}
+
+	return tweakOpts
+}
+
 // MuSig2ParsePubKeys parses a list of raw public keys as the signing keys of a
 // MuSig2 signing session.
-func MuSig2ParsePubKeys(rawPubKeys [][]byte) ([]*btcec.PublicKey, error) {
+func MuSig2ParsePubKeys(bipVersion MuSig2Version,
+	rawPubKeys [][]byte) ([]*btcec.PublicKey, error) {
+
 	allSignerPubKeys := make([]*btcec.PublicKey, len(rawPubKeys))
 	if len(rawPubKeys) < 2 {
 		return nil, fmt.Errorf("need at least two signing public keys")
 	}
 
 	for idx, pubKeyBytes := range rawPubKeys {
-		pubKey, err := schnorr.ParsePubKey(pubKeyBytes)
-		if err != nil {
-			return nil, fmt.Errorf("error parsing signer public "+
-				"key %d: %v", idx, err)
+		switch bipVersion {
+		case MuSig2Version040:
+			pubKey, err := schnorr.ParsePubKey(pubKeyBytes)
+			if err != nil {
+				return nil, fmt.Errorf("error parsing signer "+
+					"public key %d for v0.4.0 (x-only "+
+					"format): %v", idx, err)
+			}
+			allSignerPubKeys[idx] = pubKey
+
+		case MuSig2Version100RC2:
+			pubKey, err := btcec.ParsePubKey(pubKeyBytes)
+			if err != nil {
+				return nil, fmt.Errorf("error parsing signer "+
+					"public key %d for v1.0.0rc2 ("+
+					"compressed format): %v", idx, err)
+			}
+			allSignerPubKeys[idx] = pubKey
+
+		default:
+			return nil, fmt.Errorf("unknown MuSig2 version: <%d>",
+				bipVersion)
 		}
-		allSignerPubKeys[idx] = pubKey
 	}
 
 	return allSignerPubKeys, nil
@@ -214,7 +285,26 @@ func MuSig2ParsePubKeys(rawPubKeys [][]byte) ([]*btcec.PublicKey, error) {
 
 // MuSig2CombineKeys combines the given set of public keys into a single
 // combined MuSig2 combined public key, applying the given tweaks.
-func MuSig2CombineKeys(allSignerPubKeys []*btcec.PublicKey, sortKeys bool,
+func MuSig2CombineKeys(bipVersion MuSig2Version,
+	allSignerPubKeys []*btcec.PublicKey, sortKeys bool,
+	tweaks *MuSig2Tweaks) (*musig2.AggregateKey, error) {
+
+	switch bipVersion {
+	case MuSig2Version040:
+		return combineKeysV040(allSignerPubKeys, sortKeys, tweaks)
+
+	case MuSig2Version100RC2:
+		return combineKeysV100RC2(allSignerPubKeys, sortKeys, tweaks)
+
+	default:
+		return nil, fmt.Errorf("unknown MuSig2 version: <%d>",
+			bipVersion)
+	}
+}
+
+// combineKeysV100rc1 implements the MuSigCombineKeys logic for the MuSig2 BIP
+// draft version 1.0.0rc2.
+func combineKeysV100RC2(allSignerPubKeys []*btcec.PublicKey, sortKeys bool,
 	tweaks *MuSig2Tweaks) (*musig2.AggregateKey, error) {
 
 	// Convert the tweak options into the appropriate MuSig2 API functional
@@ -240,8 +330,69 @@ func MuSig2CombineKeys(allSignerPubKeys []*btcec.PublicKey, sortKeys bool,
 	return combinedKey, err
 }
 
+// combineKeysV040 implements the MuSigCombineKeys logic for the MuSig2 BIP
+// draft version 0.4.0.
+func combineKeysV040(allSignerPubKeys []*btcec.PublicKey, sortKeys bool,
+	tweaks *MuSig2Tweaks) (*musig2.AggregateKey, error) {
+
+	// Convert the tweak options into the appropriate MuSig2 API functional
+	// options.
+	var keyAggOpts []musig2v040.KeyAggOption
+	switch {
+	case tweaks.TaprootBIP0086Tweak:
+		keyAggOpts = append(keyAggOpts, musig2v040.WithBIP86KeyTweak())
+	case len(tweaks.TaprootTweak) > 0:
+		keyAggOpts = append(keyAggOpts, musig2v040.WithTaprootKeyTweak(
+			tweaks.TaprootTweak,
+		))
+	case len(tweaks.GenericTweaks) > 0:
+		genericTweaksCopy := make(
+			[]musig2v040.KeyTweakDesc, len(tweaks.GenericTweaks),
+		)
+		for idx := range tweaks.GenericTweaks {
+			genericTweaksCopy[idx] = musig2v040.KeyTweakDesc{
+				Tweak:   tweaks.GenericTweaks[idx].Tweak,
+				IsXOnly: tweaks.GenericTweaks[idx].IsXOnly,
+			}
+		}
+		keyAggOpts = append(keyAggOpts, musig2v040.WithKeyTweaks(
+			genericTweaksCopy...,
+		))
+	}
+
+	// Then we'll use this information to compute the aggregated public key.
+	combinedKey, _, _, err := musig2v040.AggregateKeys(
+		allSignerPubKeys, sortKeys, keyAggOpts...,
+	)
+
+	// Copy the result back into the default version's native type.
+	return &musig2.AggregateKey{
+		FinalKey:      combinedKey.FinalKey,
+		PreTweakedKey: combinedKey.PreTweakedKey,
+	}, err
+}
+
 // MuSig2CreateContext creates a new MuSig2 signing context.
-func MuSig2CreateContext(privKey *btcec.PrivateKey,
+func MuSig2CreateContext(bipVersion MuSig2Version, privKey *btcec.PrivateKey,
+	allSignerPubKeys []*btcec.PublicKey,
+	tweaks *MuSig2Tweaks) (MuSig2Context, MuSig2Session, error) {
+
+	switch bipVersion {
+	case MuSig2Version040:
+		return createContextV040(privKey, allSignerPubKeys, tweaks)
+
+	case MuSig2Version100RC2:
+		return createContextV100RC2(privKey, allSignerPubKeys, tweaks)
+
+	default:
+		return nil, nil, fmt.Errorf("unknown MuSig2 version: <%d>",
+			bipVersion)
+	}
+}
+
+// createContextV100RC2 implements the MuSig2CreateContext logic for the MuSig2
+// BIP draft version 1.0.0rc2.
+func createContextV100RC2(privKey *btcec.PrivateKey,
 	allSignerPubKeys []*btcec.PublicKey,
 	tweaks *MuSig2Tweaks) (*musig2.Context, *musig2.Session, error) {
 
@@ -267,6 +418,35 @@ func MuSig2CreateContext(privKey *btcec.PrivateKey,
 	return muSigContext, muSigSession, nil
 }
 
+// createContextV040 implements the MuSig2CreateContext logic for the MuSig2 BIP
+// draft version 0.4.0.
+func createContextV040(privKey *btcec.PrivateKey,
+	allSignerPubKeys []*btcec.PublicKey,
+	tweaks *MuSig2Tweaks) (*musig2v040.Context, *musig2v040.Session,
+	error) {
+
+	// The context keeps track of all signing keys and our local key.
+	allOpts := append(
+		[]musig2v040.ContextOption{
+			musig2v040.WithKnownSigners(allSignerPubKeys),
+		},
+		tweaks.ToV040ContextOptions()...,
+	)
+	muSigContext, err := musig2v040.NewContext(privKey, true, allOpts...)
+	if err != nil {
+		return nil, nil, fmt.Errorf("error creating MuSig2 signing "+
+			"context: %v", err)
+	}
+
+	muSigSession, err := muSigContext.NewSession()
+	if err != nil {
+		return nil, nil, fmt.Errorf("error creating MuSig2 signing "+
+			"session: %v", err)
+	}
+
+	return muSigContext, muSigSession, nil
+}
+
 // MuSig2Sign calls the Sign() method on the given versioned signing session and
 // returns the result in the most recent version of the MuSig2 API.
 func MuSig2Sign(session MuSig2Session, msg [32]byte,
@@ -286,6 +466,22 @@ func MuSig2Sign(session MuSig2Session, msg [32]byte,
 
 		return partialSig, nil
 
+	case *musig2v040.Session:
+		var opts []musig2v040.SignOption
+		if withSortedKeys {
+			opts = append(opts, musig2v040.WithSortedKeys())
+		}
+		partialSig, err := s.Sign(msg, opts...)
+		if err != nil {
+			return nil, fmt.Errorf("error signing with local key: "+
+				"%v", err)
+		}
+
+		return &musig2.PartialSignature{
+			S: partialSig.S,
+			R: partialSig.R,
+		}, nil
+
 	default:
 		return nil, fmt.Errorf("invalid session type <%T>", s)
 	}
@@ -306,6 +502,18 @@ func MuSig2CombineSig(session MuSig2Session,
 
 		return haveAllSigs, nil
 
+	case *musig2v040.Session:
+		haveAllSigs, err := s.CombineSig(&musig2v040.PartialSignature{
+			S: otherPartialSig.S,
+			R: otherPartialSig.R,
+		})
+		if err != nil {
+			return false, fmt.Errorf("error combining partial "+
+				"signature: %v", err)
+		}
+
+		return haveAllSigs, nil
+
 	default:
 		return false, fmt.Errorf("invalid session type <%T>", s)
 	}

input/musig2_test.go

@@ -40,6 +40,19 @@ var (
 			"CA66",
 	))
 
+	testVector100Key1, _ = btcec.ParsePubKey(hexDecode(
+		"02F9308A019258C31049344F85F89D5229B531C845836F99B08601F113BC" +
+			"E036F9",
+	))
+	testVector100Key2, _ = btcec.ParsePubKey(hexDecode(
+		"03DFF1D77F2A671C5F36183726DB2341BE58FEAE1DA2DECED843240F7B50" +
+			"2BA659",
+	))
+	testVector100Key3, _ = btcec.ParsePubKey(hexDecode(
+		"023590A94E768F8E1815C2F24B4D80A8E3149316C3518CE7B7AD338368D0" +
+			"38CA66",
+	))
+
 	bip86Tweak = &MuSig2Tweaks{TaprootBIP0086Tweak: true}
 )
 
@@ -48,6 +61,7 @@ func TestMuSig2CombineKeys(t *testing.T) {
 
 	testCases := []struct {
 		name                string
+		version             MuSig2Version
 		keys                []*btcec.PublicKey
 		sortKeys            bool
 		tweak               *MuSig2Tweaks
@@ -55,16 +69,21 @@ func TestMuSig2CombineKeys(t *testing.T) {
 		expectedFinalKey    string
 		expectedPreTweakKey string
 	}{{
+		name:        "invalid version",
+		version:     7,
+		expectedErr: "unknown MuSig2 version: <7>",
+	}, {
 		name:     "v0.4.0 two dummy keys BIP86",
+		version:  MuSig2Version040,
 		keys:     []*btcec.PublicKey{dummyPubKey1, dummyPubKey2},
-		sortKeys: true,
-		tweak:    bip86Tweak,
+		sortKeys: true, tweak: bip86Tweak,
 		expectedFinalKey: "03b54fb320a8fc3589e86a1559c6aaa774fbab4e4d" +
 			"9fbf31e2fd836b661ac6a132",
 		expectedPreTweakKey: "0279c76a15dcf6786058a571e4022b78633e1bf" +
 			"8a7a4ca440bcbbeeaea772228a2",
 	}, {
-		name: "v0.4.0 three dummy keys BIP86",
+		name:    "v0.4.0 three dummy keys BIP86",
+		version: MuSig2Version040,
 		keys: []*btcec.PublicKey{
 			dummyPubKey1, dummyPubKey2, dummyPubKey3,
 		},
@@ -75,12 +94,13 @@ func TestMuSig2CombineKeys(t *testing.T) {
 		expectedPreTweakKey: "03e615b8aad4ed10544537bc48b1d6600e15773" +
 			"476a675c6cbba6808f21b1988e5",
 	}, {
-		name: "v0.4.0 three test vector keys BIP86",
+		name:    "v0.4.0 three test vector keys BIP86",
+		version: MuSig2Version040,
 		keys: []*btcec.PublicKey{
 			testVector040Key1, testVector040Key2, testVector040Key3,
 		},
-		sortKeys: true,
 		tweak:    bip86Tweak,
+		sortKeys: true,
 		expectedFinalKey: "025b257b4e785d61157ef5303051f45184bd5cb47b" +
 			"c4b4069ed4dd4536459cb83b",
 		expectedPreTweakKey: "02d70cd69a2647f7390973df48cbfa2ccc407b8" +
@@ -107,6 +127,54 @@ func TestMuSig2CombineKeys(t *testing.T) {
 			"dfdb788b3735b76a55538179",
 		expectedPreTweakKey: "03e5830140512195d74c8307e39637cbe5fb730" +
 			"ebeab80ec514cf88a877ceeee0b",
+	}, {
+		name:    "v1.0.0rc2 three dummy keys BIP86",
+		version: MuSig2Version100RC2,
+		keys: []*btcec.PublicKey{
+			dummyPubKey1, dummyPubKey2, dummyPubKey3,
+		},
+		sortKeys: true,
+		tweak:    bip86Tweak,
+		expectedFinalKey: "029d11a433e446276c88ee099cecfda1e4234dc486" +
+			"49e2b07f9b159176731eb68a",
+		expectedPreTweakKey: "03f0bacfef76086c519b6db216a252f1435336f" +
+			"d23fc86cfb51f67056439c256d4",
+	}, {
+		name:    "v1.0.0rc2 three test vector keys BIP86",
+		version: MuSig2Version100RC2,
+		keys: []*btcec.PublicKey{
+			testVector100Key1, testVector100Key2, testVector100Key3,
+		},
+		sortKeys: false,
+		tweak:    bip86Tweak,
+		expectedFinalKey: "03f79d14149ecd4bb74921865906a8e4f1333439a9" +
+			"1b96610d72caa7495dcf2376",
+		expectedPreTweakKey: "0290539eede565f5d054f32cc0c220126889ed1" +
+			"e5d193baf15aef344fe59d4610c",
+	}, {
+		name:    "v1.0.0rc2 three test vector keys BIP86 sorted",
+		version: MuSig2Version100RC2,
+		keys: []*btcec.PublicKey{
+			testVector100Key1, testVector100Key2, testVector100Key3,
+		},
+		sortKeys: true,
+		tweak:    bip86Tweak,
+		expectedFinalKey: "0379e6c3e628c9bfbce91de6b7fb28e2aec7713d37" +
+			"7cf260ab599dcbc40e542312",
+		expectedPreTweakKey: "03789d937bade6673538f3e28d8368dda4d0512" +
+			"f94da44cf477a505716d26a1575",
+	}, {
+		name:    "v1.0.0rc2 three test vector keys BIP86 reverse order",
+		version: MuSig2Version100RC2,
+		keys: []*btcec.PublicKey{
+			testVector100Key3, testVector100Key2, testVector100Key1,
+		},
+		sortKeys: false,
+		tweak:    bip86Tweak,
+		expectedFinalKey: "03d61d333ab8c53c330290c144f406ce0c0dc3564b" +
+			"8e3dee6d1daa6288609bfc75",
+		expectedPreTweakKey: "036204de8b083426dc6eaf9502d27024d53fc82" +
+			"6bf7d2012148a0575435df54b2b",
 	}}
 
 	for _, tc := range testCases {
@@ -115,7 +183,7 @@ func TestMuSig2CombineKeys(t *testing.T) {
 			tt.Parallel()
 
 			res, err := MuSig2CombineKeys(
-				tc.keys, tc.sortKeys, tc.tweak,
+				tc.version, tc.keys, tc.sortKeys, tc.tweak,
 			)
 
 			if tc.expectedErr != "" {

input/test_utils.go

@@ -139,7 +139,7 @@ func (m *MockSigner) ComputeInputScript(tx *wire.MsgTx, signDesc *SignDescriptor
 // all signing parties must be provided, including the public key of the local
 // signing key. If nonces of other parties are already known, they can be
 // submitted as well to reduce the number of method calls necessary later on.
-func (m *MockSigner) MuSig2CreateSession(keychain.KeyLocator,
+func (m *MockSigner) MuSig2CreateSession(MuSig2Version, keychain.KeyLocator,
 	[]*btcec.PublicKey, *MuSig2Tweaks,
 	[][musig2.PubNonceSize]byte) (*MuSig2SessionInfo, error) {
 

lnrpc/signrpc/signer_server.go

@@ -826,7 +826,9 @@ func (s *Server) MuSig2CombineKeys(_ context.Context,
 
 	// Parse the public keys of all signing participants. This must also
 	// include our own, local key.
-	allSignerPubKeys, err := input.MuSig2ParsePubKeys(in.AllSignerPubkeys)
+	allSignerPubKeys, err := input.MuSig2ParsePubKeys(
+		input.MuSig2Version040, in.AllSignerPubkeys,
+	)
 	if err != nil {
 		return nil, fmt.Errorf("error parsing all signer public "+
 			"keys: %w", err)
@@ -841,7 +843,7 @@ func (s *Server) MuSig2CombineKeys(_ context.Context,
 
 	// Combine the keys now without creating a session in memory.
 	combinedKey, err := input.MuSig2CombineKeys(
-		allSignerPubKeys, true, tweaks,
+		input.MuSig2Version040, allSignerPubKeys, true, tweaks,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("error combining keys: %v", err)
@@ -881,7 +883,9 @@ func (s *Server) MuSig2CreateSession(_ context.Context,
 
 	// Parse the public keys of all signing participants. This must also
 	// include our own, local key.
-	allSignerPubKeys, err := input.MuSig2ParsePubKeys(in.AllSignerPubkeys)
+	allSignerPubKeys, err := input.MuSig2ParsePubKeys(
+		input.MuSig2Version040, in.AllSignerPubkeys,
+	)
 	if err != nil {
 		return nil, fmt.Errorf("error parsing all signer public "+
 			"keys: %w", err)
@@ -913,7 +917,8 @@ func (s *Server) MuSig2CreateSession(_ context.Context,
 
 	// Register the session with the internal wallet/signer now.
 	session, err := s.cfg.Signer.MuSig2CreateSession(
-		keyLoc, allSignerPubKeys, tweaks, otherSignerNonces,
+		input.MuSig2Version040, keyLoc, allSignerPubKeys, tweaks,
+		otherSignerNonces,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("error registering session: %v", err)

lntest/mock/signer.go

@@ -55,8 +55,8 @@ func (d *DummySigner) ComputeInputScript(tx *wire.MsgTx,
 // all signing parties must be provided, including the public key of the local
 // signing key. If nonces of other parties are already known, they can be
 // submitted as well to reduce the number of method calls necessary later on.
-func (d *DummySigner) MuSig2CreateSession(keychain.KeyLocator,
-	[]*btcec.PublicKey, *input.MuSig2Tweaks,
+func (d *DummySigner) MuSig2CreateSession(input.MuSig2Version,
+	keychain.KeyLocator, []*btcec.PublicKey, *input.MuSig2Tweaks,
 	[][musig2.PubNonceSize]byte) (*input.MuSig2SessionInfo, error) {
 
 	return nil, nil
@@ -194,8 +194,8 @@ func (s *SingleSigner) SignMessage(keyLoc keychain.KeyLocator,
 // all signing parties must be provided, including the public key of the local
 // signing key. If nonces of other parties are already known, they can be
 // submitted as well to reduce the number of method calls necessary later on.
-func (s *SingleSigner) MuSig2CreateSession(keychain.KeyLocator,
-	[]*btcec.PublicKey, *input.MuSig2Tweaks,
+func (s *SingleSigner) MuSig2CreateSession(input.MuSig2Version,
+	keychain.KeyLocator, []*btcec.PublicKey, *input.MuSig2Tweaks,
 	[][musig2.PubNonceSize]byte) (*input.MuSig2SessionInfo, error) {
 
 	return nil, nil

lnwallet/btcwallet/signer.go

@@ -488,8 +488,9 @@ type muSig2State struct {
 // all signing parties must be provided, including the public key of the local
 // signing key. If nonces of other parties are already known, they can be
 // submitted as well to reduce the number of method calls necessary later on.
-func (b *BtcWallet) MuSig2CreateSession(keyLoc keychain.KeyLocator,
-	allSignerPubKeys []*btcec.PublicKey, tweaks *input.MuSig2Tweaks,
+func (b *BtcWallet) MuSig2CreateSession(bipVersion input.MuSig2Version,
+	keyLoc keychain.KeyLocator, allSignerPubKeys []*btcec.PublicKey,
+	tweaks *input.MuSig2Tweaks,
 	otherSignerNonces [][musig2.PubNonceSize]byte) (*input.MuSig2SessionInfo,
 	error) {
 
@@ -503,10 +504,10 @@ func (b *BtcWallet) MuSig2CreateSession(keyLoc keychain.KeyLocator,
 		return nil, fmt.Errorf("error deriving private key: %v", err)
 	}
 
-	// Create a signing context with the given private key and list of all
-	// known signer public keys.
+	// Create a signing context and session with the given private key and
+	// list of all known signer public keys.
 	muSigContext, muSigSession, err := input.MuSig2CreateContext(
-		privKey, allSignerPubKeys, tweaks,
+		bipVersion, privKey, allSignerPubKeys, tweaks,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("error creating signing context: %v",
@@ -535,6 +536,7 @@ func (b *BtcWallet) MuSig2CreateSession(keyLoc keychain.KeyLocator,
 			SessionID: input.NewMuSig2SessionID(
 				combinedKey, muSigSession.PublicNonce(),
 			),
+			Version:       bipVersion,
 			PublicNonce:   muSigSession.PublicNonce(),
 			CombinedKey:   combinedKey,
 			TaprootTweak:  tweaks.HasTaprootTweak(),

lnwallet/rpcwallet/rpcwallet.go

@@ -640,8 +640,9 @@ func (r *RPCKeyRing) ComputeInputScript(tx *wire.MsgTx,
 // all signing parties must be provided, including the public key of the local
 // signing key. If nonces of other parties are already known, they can be
 // submitted as well to reduce the number of method calls necessary later on.
-func (r *RPCKeyRing) MuSig2CreateSession(keyLoc keychain.KeyLocator,
-	pubKeys []*btcec.PublicKey, tweaks *input.MuSig2Tweaks,
+func (r *RPCKeyRing) MuSig2CreateSession(bipVersion input.MuSig2Version,
+	keyLoc keychain.KeyLocator, pubKeys []*btcec.PublicKey,
+	tweaks *input.MuSig2Tweaks,
 	otherNonces [][musig2.PubNonceSize]byte) (*input.MuSig2SessionInfo,
 	error) {
 
@@ -690,6 +691,7 @@ func (r *RPCKeyRing) MuSig2CreateSession(keyLoc keychain.KeyLocator,
 
 	// De-Serialize all the info back into our native struct.
 	info := &input.MuSig2SessionInfo{
+		Version:       bipVersion,
 		TaprootTweak:  tweaks.HasTaprootTweak(),
 		HaveAllNonces: resp.HaveAllNonces,
 	}

watchtower/wtmock/signer.go

@@ -69,8 +69,8 @@ func (s *MockSigner) ComputeInputScript(tx *wire.MsgTx,
 // all signing parties must be provided, including the public key of the local
 // signing key. If nonces of other parties are already known, they can be
 // submitted as well to reduce the number of method calls necessary later on.
-func (s *MockSigner) MuSig2CreateSession(keychain.KeyLocator,
-	[]*btcec.PublicKey, *input.MuSig2Tweaks,
+func (s *MockSigner) MuSig2CreateSession(input.MuSig2Version,
+	keychain.KeyLocator, []*btcec.PublicKey, *input.MuSig2Tweaks,
 	[][musig2.PubNonceSize]byte) (*input.MuSig2SessionInfo, error) {
 
 	return nil, nil