base/md5.cc

   1 // The original file was copied from sqlite, and was in the public domain.
   2 // Modifications Copyright 2006 Google Inc. All Rights Reserved
   3
   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
  21 #include "base/md5.h"
  22
  23 #include "base/basictypes.h"
  24
  25 namespace {
  26
  27 struct Context {
  28   uint32 buf[4];
  29   uint32 bits[2];
  30   unsigned char in[64];
  31 };
  32
  33 /*
  34  * Note: this code is harmless on little-endian machines.
  35  */
  36 void byteReverse(unsigned char *buf, unsigned longs) {
  37         uint32 t;
  38         do {
  39                 t = (uint32)((unsigned)buf[3]<<8 | buf[2]) << 16 |
  40                             ((unsigned)buf[1]<<8 | buf[0]);
  41                 *(uint32 *)buf = t;
  42                 buf += 4;
  43         } while (--longs);
  44 }
  45
  46 /* The four core functions - F1 is optimized somewhat */
  47
  48 /* #define F1(x, y, z) (x & y | ~x & z) */
  49 #define F1(x, y, z) (z ^ (x & (y ^ z)))
  50 #define F2(x, y, z) F1(z, x, y)
  51 #define F3(x, y, z) (x ^ y ^ z)
  52 #define F4(x, y, z) (y ^ (x | ~z))
  53
  54 /* This is the central step in the MD5 algorithm. */
  55 #define MD5STEP(f, w, x, y, z, data, s) \
  56         ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
  57
  58 /*
  59  * The core of the MD5 algorithm, this alters an existing MD5 hash to
  60  * reflect the addition of 16 longwords of new data.  MD5Update blocks
  61  * the data and converts bytes into longwords for this routine.
  62  */
  63 void MD5Transform(uint32 buf[4], const uint32 in[16]) {
  64         register uint32 a, b, c, d;
  65
  66         a = buf[0];
  67         b = buf[1];
  68         c = buf[2];
  69         d = buf[3];
  70
  71         MD5STEP(F1, a, b, c, d, in[ 0]+0xd76aa478,  7);
  72         MD5STEP(F1, d, a, b, c, in[ 1]+0xe8c7b756, 12);
  73         MD5STEP(F1, c, d, a, b, in[ 2]+0x242070db, 17);
  74         MD5STEP(F1, b, c, d, a, in[ 3]+0xc1bdceee, 22);
  75         MD5STEP(F1, a, b, c, d, in[ 4]+0xf57c0faf,  7);
  76         MD5STEP(F1, d, a, b, c, in[ 5]+0x4787c62a, 12);
  77         MD5STEP(F1, c, d, a, b, in[ 6]+0xa8304613, 17);
  78         MD5STEP(F1, b, c, d, a, in[ 7]+0xfd469501, 22);
  79         MD5STEP(F1, a, b, c, d, in[ 8]+0x698098d8,  7);
  80         MD5STEP(F1, d, a, b, c, in[ 9]+0x8b44f7af, 12);
  81         MD5STEP(F1, c, d, a, b, in[10]+0xffff5bb1, 17);
  82         MD5STEP(F1, b, c, d, a, in[11]+0x895cd7be, 22);
  83         MD5STEP(F1, a, b, c, d, in[12]+0x6b901122,  7);
  84         MD5STEP(F1, d, a, b, c, in[13]+0xfd987193, 12);
  85         MD5STEP(F1, c, d, a, b, in[14]+0xa679438e, 17);
  86         MD5STEP(F1, b, c, d, a, in[15]+0x49b40821, 22);
  87
  88         MD5STEP(F2, a, b, c, d, in[ 1]+0xf61e2562,  5);
  89         MD5STEP(F2, d, a, b, c, in[ 6]+0xc040b340,  9);
  90         MD5STEP(F2, c, d, a, b, in[11]+0x265e5a51, 14);
  91         MD5STEP(F2, b, c, d, a, in[ 0]+0xe9b6c7aa, 20);
  92         MD5STEP(F2, a, b, c, d, in[ 5]+0xd62f105d,  5);
  93         MD5STEP(F2, d, a, b, c, in[10]+0x02441453,  9);
  94         MD5STEP(F2, c, d, a, b, in[15]+0xd8a1e681, 14);
  95         MD5STEP(F2, b, c, d, a, in[ 4]+0xe7d3fbc8, 20);
  96         MD5STEP(F2, a, b, c, d, in[ 9]+0x21e1cde6,  5);
  97         MD5STEP(F2, d, a, b, c, in[14]+0xc33707d6,  9);
  98         MD5STEP(F2, c, d, a, b, in[ 3]+0xf4d50d87, 14);
  99         MD5STEP(F2, b, c, d, a, in[ 8]+0x455a14ed, 20);
 100         MD5STEP(F2, a, b, c, d, in[13]+0xa9e3e905,  5);
 101         MD5STEP(F2, d, a, b, c, in[ 2]+0xfcefa3f8,  9);
 102         MD5STEP(F2, c, d, a, b, in[ 7]+0x676f02d9, 14);
 103         MD5STEP(F2, b, c, d, a, in[12]+0x8d2a4c8a, 20);
 104
 105         MD5STEP(F3, a, b, c, d, in[ 5]+0xfffa3942,  4);
 106         MD5STEP(F3, d, a, b, c, in[ 8]+0x8771f681, 11);
 107         MD5STEP(F3, c, d, a, b, in[11]+0x6d9d6122, 16);
 108         MD5STEP(F3, b, c, d, a, in[14]+0xfde5380c, 23);
 109         MD5STEP(F3, a, b, c, d, in[ 1]+0xa4beea44,  4);
 110         MD5STEP(F3, d, a, b, c, in[ 4]+0x4bdecfa9, 11);
 111         MD5STEP(F3, c, d, a, b, in[ 7]+0xf6bb4b60, 16);
 112         MD5STEP(F3, b, c, d, a, in[10]+0xbebfbc70, 23);
 113         MD5STEP(F3, a, b, c, d, in[13]+0x289b7ec6,  4);
 114         MD5STEP(F3, d, a, b, c, in[ 0]+0xeaa127fa, 11);
 115         MD5STEP(F3, c, d, a, b, in[ 3]+0xd4ef3085, 16);
 116         MD5STEP(F3, b, c, d, a, in[ 6]+0x04881d05, 23);
 117         MD5STEP(F3, a, b, c, d, in[ 9]+0xd9d4d039,  4);
 118         MD5STEP(F3, d, a, b, c, in[12]+0xe6db99e5, 11);
 119         MD5STEP(F3, c, d, a, b, in[15]+0x1fa27cf8, 16);
 120         MD5STEP(F3, b, c, d, a, in[ 2]+0xc4ac5665, 23);
 121
 122         MD5STEP(F4, a, b, c, d, in[ 0]+0xf4292244,  6);
 123         MD5STEP(F4, d, a, b, c, in[ 7]+0x432aff97, 10);
 124         MD5STEP(F4, c, d, a, b, in[14]+0xab9423a7, 15);
 125         MD5STEP(F4, b, c, d, a, in[ 5]+0xfc93a039, 21);
 126         MD5STEP(F4, a, b, c, d, in[12]+0x655b59c3,  6);
 127         MD5STEP(F4, d, a, b, c, in[ 3]+0x8f0ccc92, 10);
 128         MD5STEP(F4, c, d, a, b, in[10]+0xffeff47d, 15);
 129         MD5STEP(F4, b, c, d, a, in[ 1]+0x85845dd1, 21);
 130         MD5STEP(F4, a, b, c, d, in[ 8]+0x6fa87e4f,  6);
 131         MD5STEP(F4, d, a, b, c, in[15]+0xfe2ce6e0, 10);
 132         MD5STEP(F4, c, d, a, b, in[ 6]+0xa3014314, 15);
 133         MD5STEP(F4, b, c, d, a, in[13]+0x4e0811a1, 21);
 134         MD5STEP(F4, a, b, c, d, in[ 4]+0xf7537e82,  6);
 135         MD5STEP(F4, d, a, b, c, in[11]+0xbd3af235, 10);
 136         MD5STEP(F4, c, d, a, b, in[ 2]+0x2ad7d2bb, 15);
 137         MD5STEP(F4, b, c, d, a, in[ 9]+0xeb86d391, 21);
 138
 139         buf[0] += a;
 140         buf[1] += b;
 141         buf[2] += c;
 142         buf[3] += d;
 143 }
 144
 145 }  // namespace
 146
 147 namespace base {
 148
 149 /*
 150  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 151  * initialization constants.
 152  */
 153 void MD5Init(MD5Context* context) {
 154         struct Context *ctx = (struct Context *)context;
 155         ctx->buf[0] = 0x67452301;
 156         ctx->buf[1] = 0xefcdab89;
 157         ctx->buf[2] = 0x98badcfe;
 158         ctx->buf[3] = 0x10325476;
 159         ctx->bits[0] = 0;
 160         ctx->bits[1] = 0;
 161 }
 162
 163 /*
 164  * Update context to reflect the concatenation of another buffer full
 165  * of bytes.
 166  */
 167 void MD5Update(MD5Context* context, const void* inbuf, size_t len) {
 168         struct Context *ctx = (struct Context *)context;
 169         const unsigned char* buf = (const unsigned char*)inbuf;
 170         uint32 t;
 171
 172         /* Update bitcount */
 173
 174         t = ctx->bits[0];
 175         if ((ctx->bits[0] = t + ((uint32)len << 3)) < t)
 176                 ctx->bits[1]++; /* Carry from low to high */
 177         ctx->bits[1] += static_cast<uint32>(len >> 29);
 178
 179         t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */
 180
 181         /* Handle any leading odd-sized chunks */
 182
 183         if (t) {
 184                 unsigned char *p = (unsigned char *)ctx->in + t;
 185
 186                 t = 64-t;
 187                 if (len < t) {
 188                         memcpy(p, buf, len);
 189                         return;
 190                 }
 191                 memcpy(p, buf, t);
 192                 byteReverse(ctx->in, 16);
 193                 MD5Transform(ctx->buf, (uint32 *)ctx->in);
 194                 buf += t;
 195                 len -= t;
 196         }
 197
 198         /* Process data in 64-byte chunks */
 199
 200         while (len >= 64) {
 201                 memcpy(ctx->in, buf, 64);
 202                 byteReverse(ctx->in, 16);
 203                 MD5Transform(ctx->buf, (uint32 *)ctx->in);
 204                 buf += 64;
 205                 len -= 64;
 206         }
 207
 208         /* Handle any remaining bytes of data. */
 209
 210         memcpy(ctx->in, buf, len);
 211 }
 212
 213 /*
 214  * Final wrapup - pad to 64-byte boundary with the bit pattern
 215  * 1 0* (64-bit count of bits processed, MSB-first)
 216  */
 217 void MD5Final(MD5Digest* digest, MD5Context* context) {
 218         struct Context *ctx = (struct Context *)context;
 219         unsigned count;
 220         unsigned char *p;
 221
 222         /* Compute number of bytes mod 64 */
 223         count = (ctx->bits[0] >> 3) & 0x3F;
 224
 225         /* Set the first char of padding to 0x80.  This is safe since there is
 226            always at least one byte free */
 227         p = ctx->in + count;
 228         *p++ = 0x80;
 229
 230         /* Bytes of padding needed to make 64 bytes */
 231         count = 64 - 1 - count;
 232
 233         /* Pad out to 56 mod 64 */
 234         if (count < 8) {
 235                 /* Two lots of padding:  Pad the first block to 64 bytes */
 236                 memset(p, 0, count);
 237                 byteReverse(ctx->in, 16);
 238                 MD5Transform(ctx->buf, (uint32 *)ctx->in);
 239
 240                 /* Now fill the next block with 56 bytes */
 241                 memset(ctx->in, 0, 56);
 242         } else {
 243                 /* Pad block to 56 bytes */
 244                 memset(p, 0, count-8);
 245         }
 246         byteReverse(ctx->in, 14);
 247
 248         /* Append length in bits and transform */
 249         ((uint32 *)ctx->in)[ 14 ] = ctx->bits[0];
 250         ((uint32 *)ctx->in)[ 15 ] = ctx->bits[1];
 251
 252         MD5Transform(ctx->buf, (uint32 *)ctx->in);
 253         byteReverse((unsigned char *)ctx->buf, 4);
 254         memcpy(digest->a, ctx->buf, 16);
 255         memset(ctx, 0, sizeof(*ctx));    /* In case it's sensitive */
 256 }
 257
 258 std::string MD5DigestToBase16(const MD5Digest& digest) {
 259   static char const zEncode[] = "0123456789abcdef";
 260
 261   std::string ret;
 262   ret.resize(32);
 263
 264   int j = 0;
 265   for (int i = 0; i < 16; i ++) {
 266     int a = digest.a[i];
 267     ret[j++] = zEncode[(a>>4)&0xf];
 268     ret[j++] = zEncode[a & 0xf];
 269   }
 270   return ret;
 271 }
 272
 273 void MD5Sum(const void* data, size_t length, MD5Digest* digest) {
 274   MD5Context ctx;
 275   MD5Init(&ctx);
 276   MD5Update(&ctx, static_cast<const unsigned char*>(data), length);
 277   MD5Final(digest, &ctx);
 278 }
 279
 280 std::string MD5String(const std::string& str) {
 281   MD5Digest digest;
 282   MD5Sum(str.data(), str.length(), &digest);
 283   return MD5DigestToBase16(digest);
 284 }
 285
 286 }  // namespace base