xtea.c 8.6 KB

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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. * @file
  25. * @brief XTEA 32-bit implementation
  26. * @author Samuel Pitoiset
  27. * @ingroup lavu_xtea
  28. */
  29. #include "avutil.h"
  30. #include "common.h"
  31. #include "intreadwrite.h"
  32. #include "xtea.h"
  33. void av_xtea_init(AVXTEA *ctx, const uint8_t key[16])
  34. {
  35. int i;
  36. for (i = 0; i < 4; i++)
  37. ctx->key[i] = AV_RB32(key + (i << 2));
  38. }
  39. static void xtea_crypt_ecb(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
  40. int decrypt, uint8_t *iv)
  41. {
  42. uint32_t v0, v1;
  43. #if !CONFIG_SMALL
  44. uint32_t k0 = ctx->key[0];
  45. uint32_t k1 = ctx->key[1];
  46. uint32_t k2 = ctx->key[2];
  47. uint32_t k3 = ctx->key[3];
  48. #endif
  49. v0 = AV_RB32(src);
  50. v1 = AV_RB32(src + 4);
  51. if (decrypt) {
  52. #if CONFIG_SMALL
  53. int i;
  54. uint32_t delta = 0x9E3779B9U, sum = delta * 32;
  55. for (i = 0; i < 32; i++) {
  56. v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
  57. sum -= delta;
  58. v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
  59. }
  60. #else
  61. #define DSTEP(SUM, K0, K1) \
  62. v1 -= (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (SUM + K0); \
  63. v0 -= (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (SUM - 0x9E3779B9U + K1)
  64. DSTEP(0xC6EF3720U, k2, k3);
  65. DSTEP(0x28B7BD67U, k3, k2);
  66. DSTEP(0x8A8043AEU, k0, k1);
  67. DSTEP(0xEC48C9F5U, k1, k0);
  68. DSTEP(0x4E11503CU, k2, k3);
  69. DSTEP(0xAFD9D683U, k2, k2);
  70. DSTEP(0x11A25CCAU, k3, k1);
  71. DSTEP(0x736AE311U, k0, k0);
  72. DSTEP(0xD5336958U, k1, k3);
  73. DSTEP(0x36FBEF9FU, k1, k2);
  74. DSTEP(0x98C475E6U, k2, k1);
  75. DSTEP(0xFA8CFC2DU, k3, k0);
  76. DSTEP(0x5C558274U, k0, k3);
  77. DSTEP(0xBE1E08BBU, k1, k2);
  78. DSTEP(0x1FE68F02U, k1, k1);
  79. DSTEP(0x81AF1549U, k2, k0);
  80. DSTEP(0xE3779B90U, k3, k3);
  81. DSTEP(0x454021D7U, k0, k2);
  82. DSTEP(0xA708A81EU, k1, k1);
  83. DSTEP(0x08D12E65U, k1, k0);
  84. DSTEP(0x6A99B4ACU, k2, k3);
  85. DSTEP(0xCC623AF3U, k3, k2);
  86. DSTEP(0x2E2AC13AU, k0, k1);
  87. DSTEP(0x8FF34781U, k0, k0);
  88. DSTEP(0xF1BBCDC8U, k1, k3);
  89. DSTEP(0x5384540FU, k2, k2);
  90. DSTEP(0xB54CDA56U, k3, k1);
  91. DSTEP(0x1715609DU, k0, k0);
  92. DSTEP(0x78DDE6E4U, k0, k3);
  93. DSTEP(0xDAA66D2BU, k1, k2);
  94. DSTEP(0x3C6EF372U, k2, k1);
  95. DSTEP(0x9E3779B9U, k3, k0);
  96. #endif
  97. if (iv) {
  98. v0 ^= AV_RB32(iv);
  99. v1 ^= AV_RB32(iv + 4);
  100. memcpy(iv, src, 8);
  101. }
  102. } else {
  103. #if CONFIG_SMALL
  104. int i;
  105. uint32_t sum = 0, delta = 0x9E3779B9U;
  106. for (i = 0; i < 32; i++) {
  107. v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (sum + ctx->key[sum & 3]);
  108. sum += delta;
  109. v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (sum + ctx->key[(sum >> 11) & 3]);
  110. }
  111. #else
  112. #define ESTEP(SUM, K0, K1) \
  113. v0 += (((v1 << 4) ^ (v1 >> 5)) + v1) ^ (SUM + K0);\
  114. v1 += (((v0 << 4) ^ (v0 >> 5)) + v0) ^ (SUM + 0x9E3779B9U + K1)
  115. ESTEP(0x00000000U, k0, k3);
  116. ESTEP(0x9E3779B9U, k1, k2);
  117. ESTEP(0x3C6EF372U, k2, k1);
  118. ESTEP(0xDAA66D2BU, k3, k0);
  119. ESTEP(0x78DDE6E4U, k0, k0);
  120. ESTEP(0x1715609DU, k1, k3);
  121. ESTEP(0xB54CDA56U, k2, k2);
  122. ESTEP(0x5384540FU, k3, k1);
  123. ESTEP(0xF1BBCDC8U, k0, k0);
  124. ESTEP(0x8FF34781U, k1, k0);
  125. ESTEP(0x2E2AC13AU, k2, k3);
  126. ESTEP(0xCC623AF3U, k3, k2);
  127. ESTEP(0x6A99B4ACU, k0, k1);
  128. ESTEP(0x08D12E65U, k1, k1);
  129. ESTEP(0xA708A81EU, k2, k0);
  130. ESTEP(0x454021D7U, k3, k3);
  131. ESTEP(0xE3779B90U, k0, k2);
  132. ESTEP(0x81AF1549U, k1, k1);
  133. ESTEP(0x1FE68F02U, k2, k1);
  134. ESTEP(0xBE1E08BBU, k3, k0);
  135. ESTEP(0x5C558274U, k0, k3);
  136. ESTEP(0xFA8CFC2DU, k1, k2);
  137. ESTEP(0x98C475E6U, k2, k1);
  138. ESTEP(0x36FBEF9FU, k3, k1);
  139. ESTEP(0xD5336958U, k0, k0);
  140. ESTEP(0x736AE311U, k1, k3);
  141. ESTEP(0x11A25CCAU, k2, k2);
  142. ESTEP(0xAFD9D683U, k3, k2);
  143. ESTEP(0x4E11503CU, k0, k1);
  144. ESTEP(0xEC48C9F5U, k1, k0);
  145. ESTEP(0x8A8043AEU, k2, k3);
  146. ESTEP(0x28B7BD67U, k3, k2);
  147. #endif
  148. }
  149. AV_WB32(dst, v0);
  150. AV_WB32(dst + 4, v1);
  151. }
  152. void av_xtea_crypt(AVXTEA *ctx, uint8_t *dst, const uint8_t *src, int count,
  153. uint8_t *iv, int decrypt)
  154. {
  155. int i;
  156. if (decrypt) {
  157. while (count--) {
  158. xtea_crypt_ecb(ctx, dst, src, decrypt, iv);
  159. src += 8;
  160. dst += 8;
  161. }
  162. } else {
  163. while (count--) {
  164. if (iv) {
  165. for (i = 0; i < 8; i++)
  166. dst[i] = src[i] ^ iv[i];
  167. xtea_crypt_ecb(ctx, dst, dst, decrypt, NULL);
  168. memcpy(iv, dst, 8);
  169. } else {
  170. xtea_crypt_ecb(ctx, dst, src, decrypt, NULL);
  171. }
  172. src += 8;
  173. dst += 8;
  174. }
  175. }
  176. }
  177. #ifdef TEST
  178. #include <stdio.h>
  179. #define XTEA_NUM_TESTS 6
  180. static const uint8_t xtea_test_key[XTEA_NUM_TESTS][16] = {
  181. { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  182. 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
  183. { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  184. 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
  185. { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  186. 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f },
  187. { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  188. 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
  189. { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  190. 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
  191. { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  192. 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }
  193. };
  194. static const uint8_t xtea_test_pt[XTEA_NUM_TESTS][8] = {
  195. { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
  196. { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
  197. { 0x5a, 0x5b, 0x6e, 0x27, 0x89, 0x48, 0xd7, 0x7f },
  198. { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48 },
  199. { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
  200. { 0x70, 0xe1, 0x22, 0x5d, 0x6e, 0x4e, 0x76, 0x55 }
  201. };
  202. static const uint8_t xtea_test_ct[XTEA_NUM_TESTS][8] = {
  203. { 0x49, 0x7d, 0xf3, 0xd0, 0x72, 0x61, 0x2c, 0xb5 },
  204. { 0xe7, 0x8f, 0x2d, 0x13, 0x74, 0x43, 0x41, 0xd8 },
  205. { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 },
  206. { 0xa0, 0x39, 0x05, 0x89, 0xf8, 0xb8, 0xef, 0xa5 },
  207. { 0xed, 0x23, 0x37, 0x5a, 0x82, 0x1a, 0x8c, 0x2d },
  208. { 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41, 0x41 }
  209. };
  210. static void test_xtea(AVXTEA *ctx, uint8_t *dst, const uint8_t *src,
  211. const uint8_t *ref, int len, uint8_t *iv, int dir,
  212. const char *test)
  213. {
  214. av_xtea_crypt(ctx, dst, src, len, iv, dir);
  215. if (memcmp(dst, ref, 8*len)) {
  216. int i;
  217. printf("%s failed\ngot ", test);
  218. for (i = 0; i < 8*len; i++)
  219. printf("%02x ", dst[i]);
  220. printf("\nexpected ");
  221. for (i = 0; i < 8*len; i++)
  222. printf("%02x ", ref[i]);
  223. printf("\n");
  224. exit(1);
  225. }
  226. }
  227. int main(void)
  228. {
  229. AVXTEA ctx;
  230. uint8_t buf[8], iv[8];
  231. int i;
  232. static const uint8_t src[32] = "HelloWorldHelloWorldHelloWorld";
  233. uint8_t ct[32];
  234. uint8_t pl[32];
  235. for (i = 0; i < XTEA_NUM_TESTS; i++) {
  236. av_xtea_init(&ctx, xtea_test_key[i]);
  237. test_xtea(&ctx, buf, xtea_test_pt[i], xtea_test_ct[i], 1, NULL, 0, "encryption");
  238. test_xtea(&ctx, buf, xtea_test_ct[i], xtea_test_pt[i], 1, NULL, 1, "decryption");
  239. /* encrypt */
  240. memcpy(iv, "HALLO123", 8);
  241. av_xtea_crypt(&ctx, ct, src, 4, iv, 0);
  242. /* decrypt into pl */
  243. memcpy(iv, "HALLO123", 8);
  244. test_xtea(&ctx, pl, ct, src, 4, iv, 1, "CBC decryption");
  245. memcpy(iv, "HALLO123", 8);
  246. test_xtea(&ctx, ct, ct, src, 4, iv, 1, "CBC inplace decryption");
  247. }
  248. printf("Test encryption/decryption success.\n");
  249. return 0;
  250. }
  251. #endif