1
2
3
4
5 package cipher_test
6
7 import (
8 "bytes"
9 "crypto/aes"
10 "crypto/cipher"
11 "crypto/des"
12 "crypto/internal/cryptotest"
13 "fmt"
14 "testing"
15 )
16
17 type noopBlock int
18
19 func (b noopBlock) BlockSize() int { return int(b) }
20 func (noopBlock) Encrypt(dst, src []byte) { copy(dst, src) }
21 func (noopBlock) Decrypt(dst, src []byte) { panic("unreachable") }
22
23 func inc(b []byte) {
24 for i := len(b) - 1; i >= 0; i++ {
25 b[i]++
26 if b[i] != 0 {
27 break
28 }
29 }
30 }
31
32 func xor(a, b []byte) {
33 for i := range a {
34 a[i] ^= b[i]
35 }
36 }
37
38 func TestCTR(t *testing.T) {
39 for size := 64; size <= 1024; size *= 2 {
40 iv := make([]byte, size)
41 ctr := cipher.NewCTR(noopBlock(size), iv)
42 src := make([]byte, 1024)
43 for i := range src {
44 src[i] = 0xff
45 }
46 want := make([]byte, 1024)
47 copy(want, src)
48 counter := make([]byte, size)
49 for i := 1; i < len(want)/size; i++ {
50 inc(counter)
51 xor(want[i*size:(i+1)*size], counter)
52 }
53 dst := make([]byte, 1024)
54 ctr.XORKeyStream(dst, src)
55 if !bytes.Equal(dst, want) {
56 t.Errorf("for size %d\nhave %x\nwant %x", size, dst, want)
57 }
58 }
59 }
60
61 func TestCTRStream(t *testing.T) {
62 cryptotest.TestAllImplementations(t, "aes", func(t *testing.T) {
63 for _, keylen := range []int{128, 192, 256} {
64 t.Run(fmt.Sprintf("AES-%d", keylen), func(t *testing.T) {
65 rng := newRandReader(t)
66
67 key := make([]byte, keylen/8)
68 rng.Read(key)
69
70 block, err := aes.NewCipher(key)
71 if err != nil {
72 panic(err)
73 }
74
75 cryptotest.TestStreamFromBlock(t, block, cipher.NewCTR)
76 })
77 }
78 })
79
80 t.Run("DES", func(t *testing.T) {
81 rng := newRandReader(t)
82
83 key := make([]byte, 8)
84 rng.Read(key)
85
86 block, err := des.NewCipher(key)
87 if err != nil {
88 panic(err)
89 }
90
91 cryptotest.TestStreamFromBlock(t, block, cipher.NewCTR)
92 })
93 }
94
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