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md5.c 7.3 KB

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  1. /*
  2. * Copyright (c) 1995 Colin Plumb. All rights reserved.
  3. * For licensing and other legal details, see the file legal.c.
  4. *
  5. * This code implements the MD5 message-digest algorithm.
  6. * The algorithm is due to Ron Rivest. This code was
  7. * written by Colin Plumb in 1993, no copyright is claimed.
  8. * This code is in the public domain; do with it what you wish.
  9. *
  10. * Equivalent code is available from RSA Data Security, Inc.
  11. * This code has been tested against that, and is equivalent,
  12. * except that you don't need to include two pages of legalese
  13. * with every copy.
  14. *
  15. * To compute the message digest of a chunk of bytes, declare an
  16. * MD5Context structure, pass it to MD5Init, call MD5Update as
  17. * needed on buffers full of bytes, and then call MD5Final, which
  18. * will fill a supplied 16-byte array with the digest.
  19. */
  20. #include "first.h"
  21. #include <string.h> /* for memcpy() */
  22. #include "md5.h"
  23. #ifndef ASM_MD5
  24. /*
  25. * Shuffle the bytes into little-endian order within words, as per the
  26. * MD5 spec. Note: this code works regardless of the byte order.
  27. */
  28. void
  29. byteSwap(word32 *buf, unsigned words)
  30. {
  31. byte *p = (byte *)buf;
  32. do {
  33. *buf++ = (word32)((unsigned)p[3] << 8 | p[2]) << 16 |
  34. ((unsigned)p[1] << 8 | p[0]);
  35. p += 4;
  36. } while (--words);
  37. }
  38. #endif
  39. /*
  40. * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
  41. * initialization constants.
  42. */
  43. void
  44. MD5Init(struct MD5Context *ctx)
  45. {
  46. ctx->buf[0] = 0x67452301;
  47. ctx->buf[1] = 0xefcdab89;
  48. ctx->buf[2] = 0x98badcfe;
  49. ctx->buf[3] = 0x10325476;
  50. ctx->bytes[0] = 0;
  51. ctx->bytes[1] = 0;
  52. }
  53. /*
  54. * Update context to reflect the concatenation of another buffer full
  55. * of bytes.
  56. */
  57. void
  58. MD5Update(struct MD5Context *ctx, byte const *buf, size_t len)
  59. {
  60. word32 t;
  61. /* Update byte count */
  62. t = ctx->bytes[0];
  63. if ((ctx->bytes[0] = t + len) < t)
  64. ctx->bytes[1]++; /* Carry from low to high */
  65. t = 64 - (t & 0x3f); /* Space available in ctx->in (at least 1) */
  66. if ((unsigned)t > len) {
  67. memcpy((byte *)ctx->in + 64 - (unsigned)t, buf, len);
  68. return;
  69. }
  70. /* First chunk is an odd size */
  71. memcpy((byte *)ctx->in + 64 - (unsigned)t, buf, (unsigned)t);
  72. byteSwap(ctx->in, 16);
  73. MD5Transform(ctx->buf, ctx->in);
  74. buf += (unsigned)t;
  75. len -= (unsigned)t;
  76. /* Process data in 64-byte chunks */
  77. while (len >= 64) {
  78. memcpy(ctx->in, buf, 64);
  79. byteSwap(ctx->in, 16);
  80. MD5Transform(ctx->buf, ctx->in);
  81. buf += 64;
  82. len -= 64;
  83. }
  84. /* Handle any remaining bytes of data. */
  85. memcpy(ctx->in, buf, len);
  86. }
  87. /*
  88. * Final wrapup - pad to 64-byte boundary with the bit pattern
  89. * 1 0* (64-bit count of bits processed, MSB-first)
  90. */
  91. void
  92. MD5Final(byte digest[16], struct MD5Context *ctx)
  93. {
  94. int count = (int)(ctx->bytes[0] & 0x3f); /* Bytes in ctx->in */
  95. byte *p = (byte *)ctx->in + count; /* First unused byte */
  96. /* Set the first char of padding to 0x80. There is always room. */
  97. *p++ = 0x80;
  98. /* Bytes of padding needed to make 56 bytes (-8..55) */
  99. count = 56 - 1 - count;
  100. if (count < 0) { /* Padding forces an extra block */
  101. memset(p, 0, count + 8);
  102. byteSwap(ctx->in, 16);
  103. MD5Transform(ctx->buf, ctx->in);
  104. p = (byte *)ctx->in;
  105. count = 56;
  106. }
  107. memset(p, 0, count);
  108. byteSwap(ctx->in, 14);
  109. /* Append length in bits and transform */
  110. ctx->in[14] = ctx->bytes[0] << 3;
  111. ctx->in[15] = ctx->bytes[1] << 3 | ctx->bytes[0] >> 29;
  112. MD5Transform(ctx->buf, ctx->in);
  113. byteSwap(ctx->buf, 4);
  114. memcpy(digest, ctx->buf, 16);
  115. memset(ctx, 0, sizeof(ctx)); /* In case it's sensitive */
  116. }
  117. #ifndef ASM_MD5
  118. /* The four core functions - F1 is optimized somewhat */
  119. /* #define F1(x, y, z) (x & y | ~x & z) */
  120. #define F1(x, y, z) (z ^ (x & (y ^ z)))
  121. #define F2(x, y, z) F1(z, x, y)
  122. #define F3(x, y, z) (x ^ y ^ z)
  123. #define F4(x, y, z) (y ^ (x | ~z))
  124. /* This is the central step in the MD5 algorithm. */
  125. #define MD5STEP(f,w,x,y,z,in,s) \
  126. (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + x)
  127. /*
  128. * The core of the MD5 algorithm, this alters an existing MD5 hash to
  129. * reflect the addition of 16 longwords of new data. MD5Update blocks
  130. * the data and converts bytes into longwords for this routine.
  131. */
  132. void
  133. MD5Transform(word32 buf[4], word32 const in[16])
  134. {
  135. register word32 a, b, c, d;
  136. a = buf[0];
  137. b = buf[1];
  138. c = buf[2];
  139. d = buf[3];
  140. MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
  141. MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
  142. MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
  143. MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
  144. MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
  145. MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
  146. MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
  147. MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
  148. MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
  149. MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
  150. MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
  151. MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
  152. MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
  153. MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
  154. MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
  155. MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
  156. MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
  157. MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
  158. MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
  159. MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
  160. MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
  161. MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
  162. MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
  163. MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
  164. MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
  165. MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
  166. MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
  167. MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
  168. MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
  169. MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
  170. MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
  171. MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
  172. MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
  173. MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
  174. MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
  175. MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
  176. MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
  177. MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
  178. MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
  179. MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
  180. MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
  181. MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
  182. MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
  183. MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
  184. MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
  185. MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
  186. MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
  187. MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
  188. MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
  189. MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
  190. MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
  191. MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
  192. MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
  193. MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
  194. MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
  195. MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
  196. MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
  197. MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
  198. MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
  199. MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
  200. MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
  201. MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
  202. MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
  203. MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
  204. buf[0] += a;
  205. buf[1] += b;
  206. buf[2] += c;
  207. buf[3] += d;
  208. }
  209. #endif