p256_asm_table_test.go

Documentation: crypto/elliptic

		 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 amd64 || arm64
		 6  // +build amd64 arm64
		 7  
		 8  package elliptic
		 9  
		10  import (
		11  	"reflect"
		12  	"testing"
		13  )
		14  
		15  func TestP256PrecomputedTable(t *testing.T) {
		16  
		17  	basePoint := []uint64{
		18  		0x79e730d418a9143c, 0x75ba95fc5fedb601, 0x79fb732b77622510, 0x18905f76a53755c6,
		19  		0xddf25357ce95560a, 0x8b4ab8e4ba19e45c, 0xd2e88688dd21f325, 0x8571ff1825885d85,
		20  		0x0000000000000001, 0xffffffff00000000, 0xffffffffffffffff, 0x00000000fffffffe,
		21  	}
		22  	t1 := make([]uint64, 12)
		23  	t2 := make([]uint64, 12)
		24  	copy(t2, basePoint)
		25  
		26  	zInv := make([]uint64, 4)
		27  	zInvSq := make([]uint64, 4)
		28  	for j := 0; j < 32; j++ {
		29  		copy(t1, t2)
		30  		for i := 0; i < 43; i++ {
		31  			// The window size is 6 so we need to double 6 times.
		32  			if i != 0 {
		33  				for k := 0; k < 6; k++ {
		34  					p256PointDoubleAsm(t1, t1)
		35  				}
		36  			}
		37  			// Convert the point to affine form. (Its values are
		38  			// still in Montgomery form however.)
		39  			p256Inverse(zInv, t1[8:12])
		40  			p256Sqr(zInvSq, zInv, 1)
		41  			p256Mul(zInv, zInv, zInvSq)
		42  
		43  			p256Mul(t1[:4], t1[:4], zInvSq)
		44  			p256Mul(t1[4:8], t1[4:8], zInv)
		45  
		46  			copy(t1[8:12], basePoint[8:12])
		47  
		48  			if got, want := p256Precomputed[i][j*8:(j*8)+8], t1[:8]; !reflect.DeepEqual(got, want) {
		49  				t.Fatalf("Unexpected table entry at [%d][%d:%d]: got %v, want %v", i, j*8, (j*8)+8, got, want)
		50  			}
		51  		}
		52  		if j == 0 {
		53  			p256PointDoubleAsm(t2, basePoint)
		54  		} else {
		55  			p256PointAddAsm(t2, t2, basePoint)
		56  		}
		57  	}
		58  
		59  }
		60
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