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xtea.c
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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 FFmpeg.
8  *
9  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
24 /**
25  * @file
26  * @brief XTEA 32-bit implementation
27  * @author Samuel Pitoiset
28  * @ingroup lavu_xtea
29  */
30 
31 #include "avutil.h"
32 #include "common.h"
33 #include "intreadwrite.h"
34 #include "mem.h"
35 #include "xtea.h"
36 
37 AVXTEA *av_xtea_alloc(void)
38 {
39  return av_mallocz(sizeof(struct AVXTEA));
40 }
41 
42 void av_xtea_init(AVXTEA *ctx, const uint8_t key[16])
43 {
44  int i;
45 
46  for (i = 0; i < 4; i++)
47  ctx->key[i] = AV_RB32(key + (i << 2));
48 }
49 
50 static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
51  int decrypt, uint8_t *iv)
52 {
53  uint32_t v0, v1;
54 #if !CONFIG_SMALL
55  uint32_t k0 = ctx->key[0];
56  uint32_t k1 = ctx->key[1];
57  uint32_t k2 = ctx->key[2];
58  uint32_t k3 = ctx->key[3];
59 #endif
60 
61  v0 = AV_RB32(src);
62  v1 = AV_RB32(src + 4);
63 
64  if (decrypt) {
65 #if CONFIG_SMALL
66  int i;
67  uint32_t delta = 0x9E3779B9U, sum = delta * 32;
68 
69  for (i = 0; i < 32; i++) {
70  v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
71  sum -= delta;
72  v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
73  }
74 #else
75 #define DSTEP(SUM, K0, K1) \
76  v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (SUM + K0); \
77  v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (SUM - 0x9E3779B9U + K1)
78 
79  DSTEP(0xC6EF3720U, k2, k3);
80  DSTEP(0x28B7BD67U, k3, k2);
81  DSTEP(0x8A8043AEU, k0, k1);
82  DSTEP(0xEC48C9F5U, k1, k0);
83  DSTEP(0x4E11503CU, k2, k3);
84  DSTEP(0xAFD9D683U, k2, k2);
85  DSTEP(0x11A25CCAU, k3, k1);
86  DSTEP(0x736AE311U, k0, k0);
87  DSTEP(0xD5336958U, k1, k3);
88  DSTEP(0x36FBEF9FU, k1, k2);
89  DSTEP(0x98C475E6U, k2, k1);
90  DSTEP(0xFA8CFC2DU, k3, k0);
91  DSTEP(0x5C558274U, k0, k3);
92  DSTEP(0xBE1E08BBU, k1, k2);
93  DSTEP(0x1FE68F02U, k1, k1);
94  DSTEP(0x81AF1549U, k2, k0);
95  DSTEP(0xE3779B90U, k3, k3);
96  DSTEP(0x454021D7U, k0, k2);
97  DSTEP(0xA708A81EU, k1, k1);
98  DSTEP(0x08D12E65U, k1, k0);
99  DSTEP(0x6A99B4ACU, k2, k3);
100  DSTEP(0xCC623AF3U, k3, k2);
101  DSTEP(0x2E2AC13AU, k0, k1);
102  DSTEP(0x8FF34781U, k0, k0);
103  DSTEP(0xF1BBCDC8U, k1, k3);
104  DSTEP(0x5384540FU, k2, k2);
105  DSTEP(0xB54CDA56U, k3, k1);
106  DSTEP(0x1715609DU, k0, k0);
107  DSTEP(0x78DDE6E4U, k0, k3);
108  DSTEP(0xDAA66D2BU, k1, k2);
109  DSTEP(0x3C6EF372U, k2, k1);
110  DSTEP(0x9E3779B9U, k3, k0);
111 #endif
112  if (iv) {
113  v0 ^= AV_RB32(iv);
114  v1 ^= AV_RB32(iv + 4);
115  memcpy(iv, src, 8);
116  }
117  } else {
118 #if CONFIG_SMALL
119  int i;
120  uint32_t sum = 0, delta = 0x9E3779B9U;
121 
122  for (i = 0; i < 32; i++) {
123  v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
124  sum += delta;
125  v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
126  }
127 #else
128 #define ESTEP(SUM, K0, K1) \
129  v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (SUM + K0);\
130  v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (SUM + 0x9E3779B9U + K1)
131  ESTEP(0x00000000U, k0, k3);
132  ESTEP(0x9E3779B9U, k1, k2);
133  ESTEP(0x3C6EF372U, k2, k1);
134  ESTEP(0xDAA66D2BU, k3, k0);
135  ESTEP(0x78DDE6E4U, k0, k0);
136  ESTEP(0x1715609DU, k1, k3);
137  ESTEP(0xB54CDA56U, k2, k2);
138  ESTEP(0x5384540FU, k3, k1);
139  ESTEP(0xF1BBCDC8U, k0, k0);
140  ESTEP(0x8FF34781U, k1, k0);
141  ESTEP(0x2E2AC13AU, k2, k3);
142  ESTEP(0xCC623AF3U, k3, k2);
143  ESTEP(0x6A99B4ACU, k0, k1);
144  ESTEP(0x08D12E65U, k1, k1);
145  ESTEP(0xA708A81EU, k2, k0);
146  ESTEP(0x454021D7U, k3, k3);
147  ESTEP(0xE3779B90U, k0, k2);
148  ESTEP(0x81AF1549U, k1, k1);
149  ESTEP(0x1FE68F02U, k2, k1);
150  ESTEP(0xBE1E08BBU, k3, k0);
151  ESTEP(0x5C558274U, k0, k3);
152  ESTEP(0xFA8CFC2DU, k1, k2);
153  ESTEP(0x98C475E6U, k2, k1);
154  ESTEP(0x36FBEF9FU, k3, k1);
155  ESTEP(0xD5336958U, k0, k0);
156  ESTEP(0x736AE311U, k1, k3);
157  ESTEP(0x11A25CCAU, k2, k2);
158  ESTEP(0xAFD9D683U, k3, k2);
159  ESTEP(0x4E11503CU, k0, k1);
160  ESTEP(0xEC48C9F5U, k1, k0);
161  ESTEP(0x8A8043AEU, k2, k3);
162  ESTEP(0x28B7BD67U, k3, k2);
163 #endif
164  }
165 
166  AV_WB32(dst, v0);
167  AV_WB32(dst + 4, v1);
168 }
169 
170 void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
171  uint8_t *iv, int decrypt)
172 {
173  int i;
174 
175  if (decrypt) {
176  while (count--) {
177  xtea_crypt_ecb(ctx, dst, src, decrypt, iv);
178 
179  src += 8;
180  dst += 8;
181  }
182  } else {
183  while (count--) {
184  if (iv) {
185  for (i = 0; i < 8; i++)
186  dst[i] = src[i] ^ iv[i];
187  xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
188  memcpy(iv, dst, 8);
189  } else {
190  xtea_crypt_ecb(ctx, dst, src, decrypt, NULL);
191  }
192  src += 8;
193  dst += 8;
194  }
195  }
196 }
197 
198 #ifdef TEST
199 #include <stdio.h>
200 
201 #define XTEA_NUM_TESTS 6
202 
203 static const uint8_t xtea_test_key[XTEA_NUM_TESTS][16] = {
204  { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
205  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
206  { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
207  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
208  { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
209  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
210  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
211  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
212  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
213  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
214  { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
215  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
216 };
217 
218 static const uint8_t xtea_test_pt[XTEA_NUM_TESTS][8] = {
219  { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
220  { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
221  { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
222  { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
223  { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
224  { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
225 };
226 
227 static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
228  { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
229  { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
230  { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
231  { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
232  { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
233  { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
234 };
235 
236 static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
237  const uint8_t *ref, int len, uint8_t *iv, int dir,
238  const char *test)
239 {
240  av_xtea_crypt(ctx, dst, src, len, iv, dir);
241  if (memcmp(dst, ref, 8*len)) {
242  int i;
243  printf("%s failed\ngot ", test);
244  for (i = 0; i < 8*len; i++)
245  printf("%02x ", dst[i]);
246  printf("\nexpected ");
247  for (i = 0; i < 8*len; i++)
248  printf("%02x ", ref[i]);
249  printf("\n");
250  exit(1);
251  }
252 }
253 
254 int main(void)
255 {
256  AVXTEA ctx;
257  uint8_t buf[8], iv[8];
258  int i;
259  static const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld";
260  uint8_t ct[32];
261  uint8_t pl[32];
262 
263  for (i = 0; i < XTEA_NUM_TESTS; i++) {
264  av_xtea_init(&ctx, xtea_test_key[i]);
265 
266  test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption");
267  test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption");
268 
269  /* encrypt */
270  memcpy(iv, "HALLO123", 8);
271  av_xtea_crypt(&ctx, ct, src, 4, iv, 0);
272 
273  /* decrypt into pl */
274  memcpy(iv, "HALLO123", 8);
275  test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption");
276 
277  memcpy(iv, "HALLO123", 8);
278  test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption");
279  }
280 
281  printf("Test encryption/decryption success.\n");
282 
283  return 0;
284 }
285 
286 #endif
NULL
#define NULL
Definition: coverity.c:32
mem.h
memory handling functions
avutil.h
external API header
ESTEP
#define ESTEP(SUM, K0, K1)
v0
GLfloat v0
Definition: opengl_enc.c:107
AVXTEA::key
uint32_t key[16]
Definition: xtea.h:37
uint8_t
uint8_t
Definition: audio_convert.c:194
delta
float delta
Definition: vorbis_enc_data.h:457
AV_RB32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_RB32
Definition: bytestream.h:87
av_xtea_crypt
void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt)
Encrypt or decrypt a buffer using a previously initialized context.
Definition: xtea.c:170
U
#define U(x)
Definition: vp56_arith.h:37
xtea_crypt_ecb
static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int decrypt, uint8_t *iv)
Definition: xtea.c:50
av_xtea_init
void av_xtea_init(AVXTEA *ctx, const uint8_t key[16])
Initialize an AVXTEA context.
Definition: xtea.c:42
count
GLsizei count
Definition: opengl_enc.c:109
test
static void test(const char *pattern, const char *host)
Definition: noproxy-test.c:23
xtea.h
Public header for libavutil XTEA algorithm.
src
AVS_Value src
Definition: avisynth_c.h:482
DSTEP
#define DSTEP(SUM, K0, K1)
buf
void * buf
Definition: avisynth_c.h:553
AV_WB32
#define AV_WB32(p, v)
Definition: intreadwrite.h:419
common.h
common internal and external API header
len
int len
Definition: vorbis_enc_data.h:452
main
int main(int argc, char **argv)
Definition: main.c:22
AVXTEA
Definition: xtea.h:36
av_xtea_alloc
AVXTEA * av_xtea_alloc(void)
Allocate an AVXTEA context.
Definition: xtea.c:37
av_mallocz
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:252
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