1187662eb2a8ecaf296c18820f1fb1808e28d92c
[libav.git] / libavutil / xtea.c
1 /*
2 * A 32-bit implementation of the XTEA algorithm
3 * Copyright (c) 2012 Samuel Pitoiset
4 *
5 * loosely based on the implementation of David Wheeler and Roger Needham
6 *
7 * This file is part of Libav.
8 *
9 * Libav is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * Libav is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with Libav; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 #include "libavutil/intreadwrite.h"
25
26 #include "avutil.h"
27 #include "common.h"
28 #include "xtea.h"
29
30 void av_xtea_init(AVXTEA *ctx, const uint8_t key[16])
31 {
32 int i;
33
34 for (i = 0; i < 4; i++)
35 ctx->key[i] = AV_RB32(key + (i << 2));
36 }
37
38 static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
39 int decrypt, uint8_t *iv)
40 {
41 uint32_t v0, v1;
42 int i;
43
44 v0 = AV_RB32(src);
45 v1 = AV_RB32(src + 4);
46
47 if (decrypt) {
48 uint32_t delta = 0x9E3779B9, sum = delta * 32;
49
50 for (i = 0; i < 32; i++) {
51 v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
52 sum -= delta;
53 v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
54 }
55 if (iv) {
56 v0 ^= AV_RB32(iv);
57 v1 ^= AV_RB32(iv + 4);
58 memcpy(iv, src, 8);
59 }
60 } else {
61 uint32_t sum = 0, delta = 0x9E3779B9;
62
63 for (i = 0; i < 32; i++) {
64 v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
65 sum += delta;
66 v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
67 }
68 }
69
70 AV_WB32(dst, v0);
71 AV_WB32(dst + 4, v1);
72 }
73
74 void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
75 uint8_t *iv, int decrypt)
76 {
77 int i;
78
79 if (decrypt) {
80 while (count--) {
81 xtea_crypt_ecb(ctx, dst, src, decrypt, iv);
82
83 src += 8;
84 dst += 8;
85 }
86 } else {
87 while (count--) {
88 if (iv) {
89 for (i = 0; i < 8; i++)
90 dst[i] = src[i] ^ iv[i];
91 xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
92 memcpy(iv, dst, 8);
93 } else {
94 xtea_crypt_ecb(ctx, dst, src, decrypt, NULL);
95 }
96 src += 8;
97 dst += 8;
98 }
99 }
100 }
101
102 #ifdef TEST
103 #include <stdio.h>
104
105 #define XTEA_NUM_TESTS 6
106
107 static const uint8_t xtea_test_key[XTEA_NUM_TESTS][16] = {
108 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
109 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
110 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
111 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
112 { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
113 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
114 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
115 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
116 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
117 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
118 { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
119 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
120 };
121
122 static const uint8_t xtea_test_pt[XTEA_NUM_TESTS][8] = {
123 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
124 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
125 { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
126 { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
127 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
128 { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
129 };
130
131 static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
132 { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
133 { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
134 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
135 { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
136 { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
137 { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
138 };
139
140 static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
141 const uint8_t *ref, int len, uint8_t *iv, int dir,
142 const char *test)
143 {
144 av_xtea_crypt(ctx, dst, src, len, iv, dir);
145 if (memcmp(dst, ref, 8*len)) {
146 int i;
147 printf("%s failed\ngot ", test);
148 for (i = 0; i < 8*len; i++)
149 printf("%02x ", dst[i]);
150 printf("\nexpected ");
151 for (i = 0; i < 8*len; i++)
152 printf("%02x ", ref[i]);
153 printf("\n");
154 exit(1);
155 }
156 }
157
158 int main(void)
159 {
160 AVXTEA ctx;
161 uint8_t buf[8], iv[8];
162 int i;
163 const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld";
164 uint8_t ct[32];
165 uint8_t pl[32];
166
167 for (i = 0; i < XTEA_NUM_TESTS; i++) {
168 av_xtea_init(&ctx, xtea_test_key[i]);
169
170 test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption");
171 test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption");
172
173 /* encrypt */
174 memcpy(iv, "HALLO123", 8);
175 av_xtea_crypt(&ctx, ct, src, 4, iv, 0);
176
177 /* decrypt into pl */
178 memcpy(iv, "HALLO123", 8);
179 test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption");
180
181 memcpy(iv, "HALLO123", 8);
182 test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption");
183 }
184 printf("Test encryption/decryption success.\n");
185
186 return 0;
187 }
188
189 #endif