Creates ValidationSignature helper

curve/curve.go

@@ -722,3 +722,48 @@ func (sc StarkCurve) PrivateToPoint(privKey *big.Int) (x, y *big.Int, err error)
 	x, y = sc.EcMult(privKey, sc.EcGenX, sc.EcGenY)
 	return x, y, nil
 }
+
+// VerifySignature verifies the ECDSA signature of a given message hash using the provided public key.
+//
+// It takes the message hash, the r and s values of the signature, and the public key as strings and
+// verifies the signature using the public key.
+//
+// Parameters:
+// - msgHash: The hash of the message to be verified as a string
+// - r: The r value (the first part) of the signature as a string
+// - s: The s value (the second part) of the signature as a string
+// - pubKey: The public key (only the x coordinate) as a string
+// Return values:
+// - bool: A boolean indicating whether the signature is valid
+// - error: An error if any occurred during the verification process
+func VerifySignature(msgHash, r, s, pubKey string) bool {
+	feltMsgHash, err := new(felt.Felt).SetString(msgHash)
+	if err != nil {
+		return false
+	}
+	feltR, err := new(felt.Felt).SetString(r)
+	if err != nil {
+		return false
+	}
+	feltS, err := new(felt.Felt).SetString(s)
+	if err != nil {
+		return false
+	}
+	pubKeyFelt, err := new(felt.Felt).SetString(pubKey)
+	if err != nil {
+		return false
+	}
+
+	signature := junoCrypto.Signature{
+		R: *feltR,
+		S: *feltS,
+	}
+
+	pubKeyStruct := junoCrypto.NewPublicKey(pubKeyFelt)
+	resp, err := pubKeyStruct.Verify(&signature, feltMsgHash)
+	if err != nil {
+		return false
+	}
+
+	return resp
+}

curve/curve_test.go

@@ -501,3 +501,28 @@ func TestGeneral_SplitFactStr(t *testing.T) {
 		require.Equal(t, d["h"], h)
 	}
 }
+
+// TestGeneral_VerifySignature is a test function that verifies the correctness of the VerifySignature function.
+//
+// It checks if the signature of a given message hash is valid using the provided r, s values and the public key.
+// The function takes no parameters and returns no values.
+//
+// Parameters:
+// - t: The testing.T object for running the test
+// Returns:
+//
+//	none
+func TestGeneral_VerifySignature(t *testing.T) {
+	// values verified with starknet.js
+
+	msgHash := "0x2789daed76c8b750d5a609a706481034db9dc8b63ae01f505d21e75a8fc2336"
+	r := "0x13e4e383af407f7ccc1f13195ff31a58cad97bbc6cf1d532798b8af616999d4"
+	s := "0x44dd06cf67b2ba7ea4af346d80b0b439e02a0b5893c6e4dfda9ee204211c879"
+	fullPubKey := "0x6c7c4408e178b2999cef9a5b3fa2a3dffc876892ad6a6bd19d1451a2256906c"
+
+	require.True(t, VerifySignature(msgHash, r, s, fullPubKey))
+
+	// Change the last digit of the message hash to test invalid signature
+	wrongMsgHash := "0x2789daed76c8b750d5a609a706481034db9dc8b63ae01f505d21e75a8fc2337"
+	require.False(t, VerifySignature(wrongMsgHash, r, s, fullPubKey))
+}

examples/typedData/main.go

@@ -49,15 +49,7 @@ func main() {
 	fmt.Println("Signature:", signature)
 
 	// This is how you can verify the signature
-	privKeyBI, ok := new(big.Int).SetString(setup.GetPrivateKey(), 0)
-	if !ok {
-		panic("Fail to convert privKey to bitInt")
-	}
-	x, y, err := curve.Curve.PrivateToPoint(privKeyBI)
-	if err != nil {
-		panic(fmt.Errorf("fail to get point: %w", err))
-	}
-	isValid := curve.Curve.Verify(messageHash.BigInt(new(big.Int)), signature[0].BigInt(new(big.Int)), signature[1].BigInt(new(big.Int)), x, y)
+	isValid := curve.VerifySignature(messageHash.String(), signature[0].String(), signature[1].String(), setup.GetPublicKey())
 	fmt.Println("Verification result:", isValid)
 }