Add secp256k1 check of pubk for btcec & go-blindsecp256k1

pubk-comp-ethereum-blindsigsecp256k1/check_test.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"crypto/ecdsa"
+	"math/big"
+	"testing"
+
+	"github.com/arnaucube/go-blindsecp256k1"
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/stretchr/testify/require"
+	"gotest.tools/assert"
+)
+
+func calculateKeysFromK(t *testing.T, k *big.Int) (*btcec.PublicKey, *blindsecp256k1.PublicKey) {
+	curve := btcec.S256()
+
+	x, y := curve.ScalarBaseMult(k.Bytes())
+
+	skEth := (*btcec.PrivateKey)(&ecdsa.PrivateKey{
+		PublicKey: ecdsa.PublicKey{
+			Curve: curve,
+			X:     x,
+			Y:     y,
+		},
+		D: k,
+	})
+	pkEthAux := (*btcec.PublicKey)(&skEth.PublicKey)
+	pkEth := skEth.PubKey()
+	assert.Equal(t, pkEth, pkEthAux)
+
+	skBlind := blindsecp256k1.PrivateKey(*k)
+	pkBlind := skBlind.Public()
+
+	return pkEth, pkBlind
+}
+
+func TestCompatibleKeys(t *testing.T) {
+	// using incremental k
+	for i := 0; i < 10000; i++ {
+		k := big.NewInt(int64(i))
+
+		pkEth, pkBlind := calculateKeysFromK(t, k)
+		assert.Equal(t, pkEth.X.String(), pkBlind.X.String())
+		assert.Equal(t, pkEth.Y.String(), pkBlind.Y.String())
+		// fmt.Println("k", k)
+		// fmt.Println(pkEth)
+		// fmt.Println(pkBlind)
+	}
+
+	// using random k
+	for i := 0; i < 10000; i++ {
+		kaux, err := btcec.NewPrivateKey(btcec.S256())
+		require.NoError(t, err)
+		k := kaux.D
+
+		pkEth, pkBlind := calculateKeysFromK(t, k)
+		assert.Equal(t, pkEth.X.String(), pkBlind.X.String())
+		assert.Equal(t, pkEth.Y.String(), pkBlind.Y.String())
+		// fmt.Println("k", k)
+		// fmt.Println(pkEth)
+		// fmt.Println(pkBlind)
+	}
+}