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 u32 t; 28 do { 29 t = (u32)((unsigned)buf[3] << 8 | buf[2]) << 16 | 30 ((unsigned)buf[1] << 8 | buf[0]); 31 *(u32*)buf = t; 32 buf += 4; 33 } while (--longs); 34 } 35 #endif 36 37 static void MD5Transform(u32 buf[4], u32 const in[16]); 38 39 /* 40 * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious 41 * initialization constants. 42 */ 43 void MD5Init(struct MD5Context* ctx) { 44 ctx->buf[0] = 0x67452301; 45 ctx->buf[1] = 0xefcdab89; 46 ctx->buf[2] = 0x98badcfe; 47 ctx->buf[3] = 0x10325476; 48 49 ctx->bits[0] = 0; 50 ctx->bits[1] = 0; 51 } 52 53 /* 54 * Update context to reflect the concatenation of another buffer full 55 * of bytes. 56 */ 57 void MD5Update(struct MD5Context* ctx, unsigned char const* buf, unsigned len) { 58 u32 t; 59 60 /* Update bitcount */ 61 62 t = ctx->bits[0]; 63 if ((ctx->bits[0] = t + ((u32)len << 3)) < t) 64 ctx->bits[1]++; /* Carry from low to high */ 65 ctx->bits[1] += len >> 29; 66 67 t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */ 68 69 /* Handle any leading odd-sized chunks */ 70 71 if (t) { 72 unsigned char* p = (unsigned char*)ctx->in + t; 73 74 t = 64 - t; 75 if (len < t) { 76 memcpy(p, buf, len); 77 return; 78 } 79 memcpy(p, buf, t); 80 byteReverse(ctx->in, 16); 81 MD5Transform(ctx->buf, (u32*)ctx->in); 82 buf += t; 83 len -= t; 84 } 85 /* Process data in 64-byte chunks */ 86 87 while (len >= 64) { 88 memcpy(ctx->in, buf, 64); 89 byteReverse(ctx->in, 16); 90 MD5Transform(ctx->buf, (u32*)ctx->in); 91 buf += 64; 92 len -= 64; 93 } 94 95 /* Handle any remaining bytes of data. */ 96 97 memcpy(ctx->in, buf, len); 98 } 99 100 /* 101 * Final wrapup - pad to 64-byte boundary with the bit pattern 102 * 1 0* (64-bit count of bits processed, MSB-first) 103 */ 104 void MD5Final(unsigned char digest[16], struct MD5Context* ctx) { 105 unsigned count; 106 unsigned char* p; 107 108 /* Compute number of bytes mod 64 */ 109 count = (ctx->bits[0] >> 3) & 0x3F; 110 111 /* Set the first char of padding to 0x80. This is safe since there is 112 always at least one byte free */ 113 p = ctx->in + count; 114 *p++ = 0x80; 115 116 /* Bytes of padding needed to make 64 bytes */ 117 count = 64 - 1 - count; 118 119 /* Pad out to 56 mod 64 */ 120 if (count < 8) { 121 /* Two lots of padding: Pad the first block to 64 bytes */ 122 memset(p, 0, count); 123 byteReverse(ctx->in, 16); 124 MD5Transform(ctx->buf, (u32*)ctx->in); 125 126 /* Now fill the next block with 56 bytes */ 127 memset(ctx->in, 0, 56); 128 } else { 129 /* Pad block to 56 bytes */ 130 memset(p, 0, count - 8); 131 } 132 byteReverse(ctx->in, 14); 133 134 /* Append length in bits and transform */ 135 ((u32*)ctx->in)[14] = ctx->bits[0]; 136 ((u32*)ctx->in)[15] = ctx->bits[1]; 137 138 MD5Transform(ctx->buf, (u32*)ctx->in); 139 byteReverse((unsigned char*)ctx->buf, 4); 140 memcpy(digest, ctx->buf, 16); 141 memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */ 142 } 143 144 /* The four core functions - F1 is optimized somewhat */ 145 146 /* #define F1(x, y, z) (x & y | ~x & z) */ 147 #define F1(x, y, z) (z ^ (x & (y ^ z))) 148 #define F2(x, y, z) F1(z, x, y) 149 #define F3(x, y, z) (x ^ y ^ z) 150 #define F4(x, y, z) (y ^ (x | ~z)) 151 152 /* This is the central step in the MD5 algorithm. */ 153 #define MD5STEP(f, w, x, y, z, data, s) \ 154 (w += f(x, y, z) + data, w = w << s | w >> (32 - s), w += x) 155 156 /* 157 * The core of the MD5 algorithm, this alters an existing MD5 hash to 158 * reflect the addition of 16 longwords of new data. MD5Update blocks 159 * the data and converts bytes into longwords for this routine. 160 */ 161 static void MD5Transform(u32 buf[4], u32 const in[16]) { 162 u32 a, b, c, d; 163 164 a = buf[0]; 165 b = buf[1]; 166 c = buf[2]; 167 d = buf[3]; 168 169 MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7); 170 MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12); 171 MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17); 172 MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22); 173 MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7); 174 MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12); 175 MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17); 176 MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22); 177 MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7); 178 MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12); 179 MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17); 180 MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22); 181 MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7); 182 MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12); 183 MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17); 184 MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22); 185 186 MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5); 187 MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9); 188 MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14); 189 MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20); 190 MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5); 191 MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9); 192 MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14); 193 MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20); 194 MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5); 195 MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9); 196 MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14); 197 MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20); 198 MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5); 199 MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9); 200 MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14); 201 MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20); 202 203 MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4); 204 MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11); 205 MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16); 206 MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23); 207 MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4); 208 MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11); 209 MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16); 210 MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23); 211 MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4); 212 MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11); 213 MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16); 214 MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23); 215 MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4); 216 MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11); 217 MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16); 218 MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23); 219 220 MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6); 221 MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10); 222 MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15); 223 MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21); 224 MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6); 225 MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10); 226 MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15); 227 MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21); 228 MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6); 229 MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10); 230 MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15); 231 MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21); 232 MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6); 233 MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10); 234 MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15); 235 MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21); 236 237 buf[0] += a; 238 buf[1] += b; 239 buf[2] += c; 240 buf[3] += d; 241 } 242