add signing with tweak type

Author: keithsue

api/side/lending/query.pulsar.go

@@ -72,18 +72,22 @@ enum SigningStatus {
 enum SigningType {
     // SIGNING_TYPE_SCHNORR defines the common schnorr signing
     SIGNING_TYPE_SCHNORR = 0;
+    // SIGNING_TYPE_SCHNORR_WITH_TWEAK defines the schnorr signing with tweak
+    SIGNING_TYPE_SCHNORR_WITH_TWEAK = 1;
     // SIGNING_TYPE_SCHNORR_WITH_COMMITMENT defines the schnorr signing with commitment
-    SIGNING_TYPE_SCHNORR_WITH_COMMITMENT = 1;
+    SIGNING_TYPE_SCHNORR_WITH_COMMITMENT = 2;
     // SIGNING_TYPE_SCHNORR_ADAPTOR defines the schnorr adaptor signing
-    SIGNING_TYPE_SCHNORR_ADAPTOR = 2;
+    SIGNING_TYPE_SCHNORR_ADAPTOR = 3;
 }
 
 // Signing Options
 message SigningOptions {
+    // optional tweak
+    string tweak = 1;
     // optional public nonce, i.e. commitment
-    string nonce = 1;
+    string nonce = 2;
     // optional adaptor point
-    string adaptor_point = 2;
+    string adaptor_point = 3;
 }
 
 // Signing Request

api/side/tss/tss.pulsar.go

@@ -35,6 +35,7 @@ func (k Keeper) HandleSettlementSignatures(ctx sdk.Context, sender string, liqui
 	}
 
 	dcmPubKey, _ := hex.DecodeString(liquidation.DCM)
+	verificationKey := types.GetTaprootOutKey(dcmPubKey)
 
 	for i, input := range settlementTxPsbt.Inputs {
 		sigHash, err := types.CalcTaprootSigHash(settlementTxPsbt, i, input.SighashType)
@@ -44,7 +45,7 @@ func (k Keeper) HandleSettlementSignatures(ctx sdk.Context, sender string, liqui
 
 		sigBytes, _ := hex.DecodeString(signatures[i])
 
-		if !schnorr.Verify(sigBytes, sigHash, dcmPubKey) {
+		if !schnorr.Verify(sigBytes, sigHash, verificationKey) {
 			return types.ErrInvalidSignature
 		}
 

docs/static/openapi.yml

@@ -55,6 +55,6 @@ func handleCompletedLiquidations(ctx sdk.Context, k keeper.Keeper) {
 		k.SetLiquidation(ctx, liquidation)
 
 		// initiate signing request via TSS
-		k.TSSKeeper().InitiateSigningRequest(ctx, types.ModuleName, types.ToScopedId(liquidation.Id), tsstypes.SigningType_SIGNING_TYPE_SCHNORR, int32(types.SigningIntent_SIGNING_INTENT_DEFAULT), liquidation.DCM, sigHashes, nil)
+		k.TSSKeeper().InitiateSigningRequest(ctx, types.ModuleName, types.ToScopedId(liquidation.Id), tsstypes.SigningType_SIGNING_TYPE_SCHNORR_WITH_TWEAK, int32(types.SigningIntent_SIGNING_INTENT_DEFAULT), liquidation.DCM, sigHashes, &tsstypes.SigningOptions{Tweak: ""})
 	}
 }

proto/side/tss/tss.proto

@@ -5,6 +5,9 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/btcsuite/btcd/btcec/v2/schnorr"
+	"github.com/btcsuite/btcd/txscript"
+
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
 
@@ -16,6 +19,16 @@ func GetPricePair(liquidation *Liquidation) string {
 	return fmt.Sprintf("%s%s", strings.ToUpper(liquidation.CollateralAsset.PriceSymbol), strings.ToUpper(liquidation.DebtAsset.PriceSymbol))
 }
 
+// GetTaprootOutKey gets the taproot output key according to the given pub key
+// Assume that the given pub key is valid taproot pub key
+func GetTaprootOutKey(pubKeyBytes []byte) []byte {
+	pubKey, _ := schnorr.ParsePubKey(pubKeyBytes)
+
+	taprootOutKey := txscript.ComputeTaprootKeyNoScript(pubKey)
+
+	return schnorr.SerializePubKey(taprootOutKey)
+}
+
 // ToScopedId converts the given local id to the scoped id
 func ToScopedId(id uint64) string {
 	return fmt.Sprintf("%d", id)

x/lending/types/query.pb.go

@@ -91,6 +91,9 @@ func GetRefreshingCompletionSigMsg(id uint64, pubKeys []string) []byte {
 // Assume that the options match the signing type
 func GetSigningOption(signingType SigningType, options *SigningOptions) string {
 	switch signingType {
+	case SigningType_SIGNING_TYPE_SCHNORR_WITH_TWEAK:
+		return options.Tweak
+
 	case SigningType_SIGNING_TYPE_SCHNORR_WITH_COMMITMENT:
 		return options.Nonce