curvepoint_test.go

package main

import (
	"crypto/sha256"
	"math/big"
	"testing"
)

func TestCurvepointGenerate(t *testing.T) {
	Ap, As, err := generateKeyPair()
	if err != nil {
		t.Fatal(err)
	}
	if !Ap.IsOnCurve() {
		t.Fatal("Generated invalid public key")
	}
	if !isValidSecretKey(As) {
		t.Fatal("Generated invalid secret key")
	}
}

func TestHashToCurve(t *testing.T) {
	testX, _ := new(big.Int).SetString("18149469767584732552991861025120904666601524803017597654373315627649680264678", 10)
	testY, _ := new(big.Int).SetString("18593544354303197021588991433499968191850988132424885073381608163097237734820", 10)

	testP := new(CurvePoint).SetFromXY(testX, testY)
	if !testP.IsOnCurve() {
		t.Fatal("Test vector not on curve")
	}

	h := sha256.Sum256([]byte("hello world"))
	p := NewCurvePointFromHash(h)

	x, y := p.GetXY()
	if x.Cmp(testX) != 0 || y.Cmp(testY) != 0 {
		t.Fatal("HashToCurve(sha256('1')), got", x, y, "expected", testX, testY)
	}
}

// This verifies that the Generator for the G1 curve is correct
// See: https://github.com/ethereum/go-ethereum/pull/15591
func TestCurvepointBaseMult(t *testing.T) {
	h := sha256.Sum256([]byte("1"))
	a := new(big.Int).SetBytes(h[:])

	// Verify sha256 hash of "1" is correct
	// sha256("1").hexdigest()
	aTest, _ := new(big.Int).SetString("6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b", 16)
	if a.Cmp(aTest) != 0 {
		t.Fatal("sha('1') test vector incorrect")
	}

	// Create 'public key' from private key of sha256("1")
	// Python equivalent: bn128.multiply(bn128.G1, int(sha256("1").hexdigest(), 16))
	b := CurvePoint{}.ScalarBaseMult(a)
	bX, bY := b.GetXY()

	// Verify test vector from solidity and py_ecc.bn128
	testX, _ := new(big.Int).SetString("18402258484067100825836416533206638046709953333460439275068607944552700874793", 10)
	testY, _ := new(big.Int).SetString("3216486158313018618592493241388793958480998389453172132732084762339402552220", 10)
	if bX.Cmp(testX) != 0 || bY.Cmp(testY) != 0 {
		t.Fatal("Test vector incorrect, ", b, "should be", testX, testY)
	}

	// Verify CurvePoint can be unserialized from the outputs it gives you
	c := new(CurvePoint).SetFromXY(bX, bY)
	if c == nil {
		t.Fatal("CurvePoint unserialize failed, presumably given invalid points", b, bX, bY, c)
	}
	if !c.Equals(&b) {
		t.Fatal("Points not equal after serialize > unserialize", b, c)
	}
}