1 /* 2 * written by Colin Plumb in 1993, no copyright is claimed. 3 * This code is in the public domain; do with it what you wish. 4 * 5 * Equivalent code is available from RSA Data Security, Inc. 6 * This code has been tested against that, and is equivalent, 7 * except that you don't need to include two pages of legalese 8 * with every copy. 9 * 10 * To compute the message digest of a chunk of bytes, declare an 11 * MD5Context structure, pass it to MD5Init, call MD5Update as 12 * needed on buffers full of bytes, and then call MD5Final, which 13 * will fill a supplied 16-byte array with the digest. 14 */ 15 16 #include <string.h> 17 18 #include "md5.h" 19 20 #ifndef WORDS_BIGENDIAN 21 #define byteReverse(buf, len) /* Nothing */ 22 #else 23 /* 24 * Note: this code is harmless on little-endian machines. 25 */ 26 static void byteReverse(unsigned char *buf, unsigned longs) 27 { 28 u32 t; 29 do { 30 t = (u32) ((unsigned) buf[3] << 8 | buf[2]) << 16 | 31 ((unsigned) buf[1] << 8 | buf[0]); 32 *(u32 *) buf = t; 33 buf += 4; 34 } while (--longs); 35 } 36 #endif 37 38 static void MD5Transform(u32 buf[4], u32 const in[16]); 39 40 /* 41 * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious 42 * initialization constants. 43 */ 44 void 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 51 ctx->bits[0] = 0; 52 ctx->bits[1] = 0; 53 } 54 55 /* 56 * Update context to reflect the concatenation of another buffer full 57 * of bytes. 58 */ 59 void MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len) 60 { 61 u32 t; 62 63 /* Update bitcount */ 64 65 t = ctx->bits[0]; 66 if ((ctx->bits[0] = t + ((u32) len << 3)) < t) 67 ctx->bits[1]++; /* Carry from low to high */ 68 ctx->bits[1] += len >> 29; 69 70 t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */ 71 72 /* Handle any leading odd-sized chunks */ 73 74 if (t) { 75 unsigned char *p = (unsigned char *) ctx->in + t; 76 77 t = 64 - t; 78 if (len < t) { 79 memcpy(p, buf, len); 80 return; 81 } 82 memcpy(p, buf, t); 83 byteReverse(ctx->in, 16); 84 MD5Transform(ctx->buf, (u32 *) ctx->in); 85 buf += t; 86 len -= t; 87 } 88 /* Process data in 64-byte chunks */ 89 90 while (len >= 64) { 91 memcpy(ctx->in, buf, 64); 92 byteReverse(ctx->in, 16); 93 MD5Transform(ctx->buf, (u32 *) ctx->in); 94 buf += 64; 95 len -= 64; 96 } 97 98 /* Handle any remaining bytes of data. */ 99 100 memcpy(ctx->in, buf, len); 101 } 102 103 /* 104 * Final wrapup - pad to 64-byte boundary with the bit pattern 105 * 1 0* (64-bit count of bits processed, MSB-first) 106 */ 107 void MD5Final(unsigned char digest[16], struct MD5Context *ctx) 108 { 109 unsigned count; 110 unsigned char *p; 111 112 /* Compute number of bytes mod 64 */ 113 count = (ctx->bits[0] >> 3) & 0x3F; 114 115 /* Set the first char of padding to 0x80. This is safe since there is 116 always at least one byte free */ 117 p = ctx->in + count; 118 *p++ = 0x80; 119 120 /* Bytes of padding needed to make 64 bytes */ 121 count = 64 - 1 - count; 122 123 /* Pad out to 56 mod 64 */ 124 if (count < 8) { 125 /* Two lots of padding: Pad the first block to 64 bytes */ 126 memset(p, 0, count); 127 byteReverse(ctx->in, 16); 128 MD5Transform(ctx->buf, (u32 *) ctx->in); 129 130 /* Now fill the next block with 56 bytes */ 131 memset(ctx->in, 0, 56); 132 } else { 133 /* Pad block to 56 bytes */ 134 memset(p, 0, count - 8); 135 } 136 byteReverse(ctx->in, 14); 137 138 /* Append length in bits and transform */ 139 ((u32 *) ctx->in)[14] = ctx->bits[0]; 140 ((u32 *) ctx->in)[15] = ctx->bits[1]; 141 142 MD5Transform(ctx->buf, (u32 *) ctx->in); 143 byteReverse((unsigned char *) ctx->buf, 4); 144 memcpy(digest, ctx->buf, 16); 145 memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */ 146 } 147 148 /* The four core functions - F1 is optimized somewhat */ 149 150 /* #define F1(x, y, z) (x & y | ~x & z) */ 151 #define F1(x, y, z) (z ^ (x & (y ^ z))) 152 #define F2(x, y, z) F1(z, x, y) 153 #define F3(x, y, z) (x ^ y ^ z) 154 #define F4(x, y, z) (y ^ (x | ~z)) 155 156 /* This is the central step in the MD5 algorithm. */ 157 #define MD5STEP(f, w, x, y, z, data, s) \ 158 ( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x ) 159 160 /* 161 * The core of the MD5 algorithm, this alters an existing MD5 hash to 162 * reflect the addition of 16 longwords of new data. MD5Update blocks 163 * the data and converts bytes into longwords for this routine. 164 */ 165 static void MD5Transform(u32 buf[4], u32 const in[16]) 166 { 167 u32 a, b, c, d; 168 169 a = buf[0]; 170 b = buf[1]; 171 c = buf[2]; 172 d = buf[3]; 173 174 MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7); 175 MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12); 176 MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17); 177 MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22); 178 MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7); 179 MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12); 180 MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17); 181 MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22); 182 MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7); 183 MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12); 184 MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17); 185 MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22); 186 MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); 187 MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12); 188 MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17); 189 MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22); 190 191 MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5); 192 MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9); 193 MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14); 194 MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20); 195 MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5); 196 MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); 197 MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14); 198 MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20); 199 MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5); 200 MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); 201 MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14); 202 MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20); 203 MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5); 204 MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9); 205 MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14); 206 MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20); 207 208 MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4); 209 MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11); 210 MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16); 211 MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23); 212 MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4); 213 MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11); 214 MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16); 215 MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23); 216 MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); 217 MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11); 218 MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16); 219 MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23); 220 MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4); 221 MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11); 222 MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16); 223 MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23); 224 225 MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6); 226 MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10); 227 MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15); 228 MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21); 229 MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); 230 MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10); 231 MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15); 232 MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21); 233 MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6); 234 MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10); 235 MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15); 236 MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21); 237 MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6); 238 MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10); 239 MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15); 240 MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21); 241 242 buf[0] += a; 243 buf[1] += b; 244 buf[2] += c; 245 buf[3] += d; 246 } 247
