cryptodev/cipher/ctr_test.go
2017-02-21 00:25:34 +01:00

56 lines
1.1 KiB
Go

// Copyright 2015 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 cipher_test
import (
"bytes"
"crypto/cipher"
"testing"
)
type noopBlock int
func (b noopBlock) BlockSize() int { return int(b) }
func (noopBlock) Encrypt(dst, src []byte) { copy(dst, src) }
func (noopBlock) Decrypt(dst, src []byte) { copy(dst, src) }
func inc(b []byte) {
for i := len(b) - 1; i >= 0; i++ {
b[i]++
if b[i] != 0 {
break
}
}
}
func xor(a, b []byte) {
for i := range a {
a[i] ^= b[i]
}
}
func TestCTR(t *testing.T) {
for size := 64; size <= 1024; size *= 2 {
iv := make([]byte, size)
ctr := cipher.NewCTR(noopBlock(size), iv)
src := make([]byte, 1024)
for i := range src {
src[i] = 0xff
}
want := make([]byte, 1024)
copy(want, src)
counter := make([]byte, size)
for i := 1; i < len(want)/size; i++ {
inc(counter)
xor(want[i*size:(i+1)*size], counter)
}
dst := make([]byte, 1024)
ctr.XORKeyStream(dst, src)
if !bytes.Equal(dst, want) {
t.Errorf("for size %d\nhave %x\nwant %x", size, dst, want)
}
}
}