Add initial nistec project files

extra_test.go

@@ -0,0 +1,174 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package nistec_test
+
+import (
+	"bytes"
+	"crypto/elliptic"
+	"math/big"
+	"testing"
+
+	"sources.truenas.cloud/code/nistec"
+)
+
+type nistPointExtra[T any] interface {
+	Bytes() []byte
+	SetGenerator() T
+	SetBytes([]byte) (T, error)
+	Set(T) T
+	Add(T, T) T
+	Double(T) T
+	Negate(T) T
+	ScalarMult(T, []byte) (T, error)
+	ScalarBaseMult([]byte) (T, error)
+	IsInfinity() int
+	Equal(T) int
+}
+
+func TestNegate(t *testing.T) {
+	t.Run("P224", func(t *testing.T) {
+		testNegate(t, nistec.NewP224Point, elliptic.P224())
+	})
+	t.Run("P256", func(t *testing.T) {
+		testNegate(t, nistec.NewP256Point, elliptic.P256())
+	})
+	t.Run("P384", func(t *testing.T) {
+		testNegate(t, nistec.NewP384Point, elliptic.P384())
+	})
+	t.Run("P521", func(t *testing.T) {
+		testNegate(t, nistec.NewP521Point, elliptic.P521())
+	})
+}
+
+func testNegate[P nistPointExtra[P]](t *testing.T, newPoint func() P, c elliptic.Curve) {
+	p := newPoint().SetGenerator()
+	p.Add(p, p) // make a test point with z != 1
+
+	p1 := newPoint().Negate(p)
+
+	minusOne := new(big.Int).Sub(c.Params().N, big.NewInt(1)).Bytes()
+	p2, err := newPoint().ScalarMult(p, minusOne)
+	fatalIfErr(t, err)
+	if !bytes.Equal(p1.Bytes(), p2.Bytes()) {
+		t.Error("-P != [-1]P")
+	}
+
+	p.Negate(p)
+	if !bytes.Equal(p.Bytes(), p1.Bytes()) {
+		t.Error("-P (aliasing) != -P")
+	}
+}
+
+func TestEqual(t *testing.T) {
+	t.Run("P224", func(t *testing.T) {
+		testEqual(t, nistec.NewP224Point, elliptic.P224())
+	})
+	t.Run("P256", func(t *testing.T) {
+		testEqual(t, nistec.NewP256Point, elliptic.P256())
+	})
+	t.Run("P384", func(t *testing.T) {
+		testEqual(t, nistec.NewP384Point, elliptic.P384())
+	})
+	t.Run("P521", func(t *testing.T) {
+		testEqual(t, nistec.NewP521Point, elliptic.P521())
+	})
+}
+
+func testEqual[P nistPointExtra[P]](t *testing.T, newPoint func() P, c elliptic.Curve) {
+	inf := newPoint()
+	g := newPoint().SetGenerator()
+	g.Add(g, g)
+	if inf.Equal(inf) != 1 {
+		t.Error("inf != inf")
+	}
+	if g.Equal(g) != 1 {
+		t.Error("G != G")
+	}
+	if inf.Equal(g) != 0 || g.Equal(inf) != 0 {
+		t.Error("G == inf")
+	}
+	p1 := newPoint().Set(g)
+	p2 := newPoint()
+	p3 := newPoint()
+	sc := make([]byte, (c.Params().N.BitLen()+7)>>3)
+	for i := 1; i < 30; i++ {
+		sc[len(sc)-1] = byte(i)
+		_, err := p2.ScalarMult(g, sc)
+		fatalIfErr(t, err)
+		sc[len(sc)-1] = byte(i * 2)
+		_, err = p3.ScalarBaseMult(sc)
+		fatalIfErr(t, err)
+		if p1.Equal(p2) != 1 || p2.Equal(p1) != 1 {
+			t.Error("n*G != n*G (1)")
+		}
+		if p1.Equal(p3) != 1 || p3.Equal(p1) != 1 {
+			t.Error("n*G != n*G (2)")
+		}
+		if p2.Equal(p3) != 1 || p3.Equal(p2) != 1 {
+			t.Error("n*G != n*G (3)")
+		}
+		p1.Add(p1, g)
+		if p1.Equal(g) != 0 || g.Equal(p1) != 0 {
+			t.Error("n*G == G")
+		}
+	}
+}
+
+func TestInfinity(t *testing.T) {
+	t.Run("P224", func(t *testing.T) {
+		testInfinity(t, nistec.NewP224Point, elliptic.P224())
+	})
+	t.Run("P256", func(t *testing.T) {
+		testInfinity(t, nistec.NewP256Point, elliptic.P256())
+	})
+	t.Run("P384", func(t *testing.T) {
+		testInfinity(t, nistec.NewP384Point, elliptic.P384())
+	})
+	t.Run("P521", func(t *testing.T) {
+		testInfinity(t, nistec.NewP521Point, elliptic.P521())
+	})
+}
+
+func testInfinity[P nistPointExtra[P]](t *testing.T, newPoint func() P, c elliptic.Curve) {
+	inf := newPoint()
+	g := newPoint().SetGenerator()
+	g.Add(g, g)
+	if inf.IsInfinity() != 1 {
+		t.Error("inf != inf")
+	}
+	if g.IsInfinity() != 0 {
+		t.Error("G == inf")
+	}
+	p1 := newPoint().Set(g)
+	p2 := newPoint()
+	sc := make([]byte, (c.Params().N.BitLen()+7)>>3)
+	for i := 1; i < 30; i++ {
+		sc[len(sc)-1] = byte(i)
+		_, err := p2.ScalarMult(g, sc)
+		fatalIfErr(t, err)
+		if p2.IsInfinity() != 0 {
+			t.Error("n*G == inf (1)")
+		}
+		p2.Negate(p2)
+		if p2.IsInfinity() != 0 {
+			t.Error("n*G == inf (2)")
+		}
+		p2.Add(p2, p1)
+		if p2.IsInfinity() != 1 {
+			t.Error("n*G - n*G != inf")
+		}
+		p1.Add(p1, g)
+		if p1.IsInfinity() != 0 {
+			t.Error("n*G == inf (3)")
+		}
+	}
+}
+
+func fatalIfErr(t *testing.T, err error) {
+	t.Helper()
+	if err != nil {
+		t.Fatal(err)
+	}
+}