1// Copyright 2021 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5//go:build !purego && (amd64 || arm64 || ppc64le || s390x) 6 7package nistec 8 9import ( 10 "fmt" 11 "testing" 12) 13 14func TestP256PrecomputedTable(t *testing.T) { 15 base := NewP256Point().SetGenerator() 16 17 for i := 0; i < 43; i++ { 18 t.Run(fmt.Sprintf("table[%d]", i), func(t *testing.T) { 19 testP256AffineTable(t, base, &p256Precomputed[i]) 20 }) 21 22 for k := 0; k < 6; k++ { 23 base.Double(base) 24 } 25 } 26} 27 28func testP256AffineTable(t *testing.T, base *P256Point, table *p256AffineTable) { 29 p := NewP256Point() 30 zInv := new(p256Element) 31 zInvSq := new(p256Element) 32 33 for j := 0; j < 32; j++ { 34 p.Add(p, base) 35 36 // Convert p to affine coordinates. 37 p256Inverse(zInv, &p.z) 38 p256Sqr(zInvSq, zInv, 1) 39 p256Mul(zInv, zInv, zInvSq) 40 41 p256Mul(&p.x, &p.x, zInvSq) 42 p256Mul(&p.y, &p.y, zInv) 43 p.z = p256One 44 45 if p256Equal(&table[j].x, &p.x) != 1 || p256Equal(&table[j].y, &p.y) != 1 { 46 t.Fatalf("incorrect table entry at index %d", j) 47 } 48 } 49} 50