md5.cpp

Public Functions

MD5Final(unsigned char digest, MD5Context * ctx)

MD5Init(MD5Context * ctx)

MD5Transform(int buf, int in)

MD5Update(MD5Context * ctx, unsigned char * buf, unsigned int len)

  1
  2/*
  3 * This code implements the MD5 message-digest algorithm.
  4 * The algorithm is due to Ron Rivest. This code was
  5 * written by Colin Plumb in 1993, no copyright is claimed.
  6 * This code is in the public domain; do with it what you wish.
  7 *
  8 * Equivalent code is available from RSA Data Security, Inc.
  9 * This code has been tested against that, and is equivalent,
 10 * except that you don't need to include two pages of legalese
 11 * with every copy.
 12 *
 13 * To compute the message digest of a chunk of bytes, declare an
 14 * MD5Context structure, pass it to MD5Init, call MD5Update as
 15 * needed on buffers full of bytes, and then call MD5Final, which
 16 * will fill a supplied 16-byte array with the digest.
 17 */
 18
 19/* Brutally hacked by John Walker back from ANSI C to K&R (no
 20   prototypes) to maintain the tradition that Netfone will compile
 21   with Sun's original "cc". */
 22
 23#include <memory.h>      /* for memcpy() */
 24#include "md5.h"
 25
 26#ifdef sgi
 27#define HIGHFIRST
 28#endif
 29
 30#ifdef sun
 31#define HIGHFIRST
 32#endif
 33
 34#ifndef HIGHFIRST
 35#define byteReverse(buf, len) /* Nothing */
 36#else
 37/*
 38 * Note: this code is harmless on little-endian machines.
 39 */
 40void byteReverse(buf, longs)
 41    unsigned char *buf; unsigned longs;
 42{
 43    int t;
 44    do {
 45   t = (int) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
 46       ((unsigned) buf[1] << 8 | buf[0]);
 47   *(int *) buf = t;
 48   buf += 4;
 49    } while (--longs);
 50}
 51#endif
 52
 53/*
 54 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 55 * initialization constants.
 56 */
 57void MD5Init( MD5Context* ctx)
 58{
 59    ctx->buf[0] = 0x67452301;
 60    ctx->buf[1] = 0xefcdab89;
 61    ctx->buf[2] = 0x98badcfe;
 62    ctx->buf[3] = 0x10325476;
 63
 64    ctx->bits[0] = 0;
 65    ctx->bits[1] = 0;
 66}
 67
 68/*
 69 * Update context to reflect the concatenation of another buffer full
 70 * of bytes.
 71 */
 72void MD5Update( MD5Context* ctx, unsigned char* buf, unsigned int len)
 73{
 74    int t;
 75
 76    /* Update bitcount */
 77
 78    t = ctx->bits[0];
 79    if ((ctx->bits[0] = t + ((int) len << 3)) < t)
 80   ctx->bits[1]++;   /* Carry from low to high */
 81    ctx->bits[1] += len >> 29;
 82
 83    t = (t >> 3) & 0x3f;   /* Bytes already in shsInfo->data */
 84
 85    /* Handle any leading odd-sized chunks */
 86
 87    if (t) {
 88   unsigned char *p = (unsigned char *) ctx->in + t;
 89
 90   t = 64 - t;
 91   if (len < t) {
 92       memcpy(p, buf, len);
 93       return;
 94   }
 95   memcpy(p, buf, t);
 96   byteReverse(ctx->in, 16);
 97   MD5Transform(ctx->buf, (int *) ctx->in);
 98   buf += t;
 99   len -= t;
100    }
101    /* Process data in 64-byte chunks */
102
103    while (len >= 64) {
104   memcpy(ctx->in, buf, 64);
105   byteReverse(ctx->in, 16);
106   MD5Transform(ctx->buf, (int *) ctx->in);
107   buf += 64;
108   len -= 64;
109    }
110
111    /* Handle any remaining bytes of data. */
112
113    memcpy(ctx->in, buf, len);
114}
115
116/*
117 * Final wrapup - pad to 64-byte boundary with the bit pattern 
118 * 1 0* (64-bit count of bits processed, MSB-first)
119 */
120void MD5Final( unsigned char digest[16], MD5Context* ctx)
121{
122    unsigned count;
123    unsigned char *p;
124
125    /* Compute number of bytes mod 64 */
126    count = (ctx->bits[0] >> 3) & 0x3F;
127
128    /* Set the first char of padding to 0x80.  This is safe since there is
129       always at least one byte free */
130    p = ctx->in + count;
131    *p++ = 0x80;
132
133    /* Bytes of padding needed to make 64 bytes */
134    count = 64 - 1 - count;
135
136    /* Pad out to 56 mod 64 */
137    if (count < 8) {
138   /* Two lots of padding:  Pad the first block to 64 bytes */
139   memset(p, 0, count);
140   byteReverse(ctx->in, 16);
141   MD5Transform(ctx->buf, (int *) ctx->in);
142
143   /* Now fill the next block with 56 bytes */
144   memset(ctx->in, 0, 56);
145    } else {
146   /* Pad block to 56 bytes */
147   memset(p, 0, count - 8);
148    }
149    byteReverse(ctx->in, 14);
150
151    /* Append length in bits and transform */
152    ((int *) ctx->in)[14] = ctx->bits[0];
153    ((int *) ctx->in)[15] = ctx->bits[1];
154
155    MD5Transform(ctx->buf, (int *) ctx->in);
156    byteReverse((unsigned char *) ctx->buf, 4);
157    memcpy(digest, ctx->buf, 16);
158    memset(ctx, 0, sizeof(MD5Context));        /* In case it's sensitive */
159}
160
161
162/* The four core functions - F1 is optimized somewhat */
163
164/* #define F1(x, y, z) (x & y | ~x & z) */
165#define F1(x, y, z) (z ^ (x & (y ^ z)))
166#define F2(x, y, z) F1(z, x, y)
167#define F3(x, y, z) (x ^ y ^ z)
168#define F4(x, y, z) (y ^ (x | ~z))
169
170/* This is the central step in the MD5 algorithm. */
171#define MD5STEP(f, w, x, y, z, data, s) \
172   ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
173
174/*
175 * The core of the MD5 algorithm, this alters an existing MD5 hash to
176 * reflect the addition of 16 longwords of new data.  MD5Update blocks
177 * the data and converts bytes into longwords for this routine.
178 */
179void MD5Transform( int buf[4], int in[16])
180{
181    int a, b, c, d;
182
183    a = buf[0];
184    b = buf[1];
185    c = buf[2];
186    d = buf[3];
187
188    MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
189    MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
190    MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
191    MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
192    MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
193    MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
194    MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
195    MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
196    MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
197    MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
198    MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
199    MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
200    MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
201    MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
202    MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
203    MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
204
205    MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
206    MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
207    MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
208    MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
209    MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
210    MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
211    MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
212    MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
213    MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
214    MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
215    MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
216    MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
217    MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
218    MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
219    MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
220    MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
221
222    MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
223    MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
224    MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
225    MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
226    MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
227    MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
228    MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
229    MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
230    MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
231    MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
232    MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
233    MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
234    MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
235    MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
236    MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
237    MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
238
239    MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
240    MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
241    MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
242    MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
243    MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
244    MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
245    MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
246    MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
247    MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
248    MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
249    MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
250    MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
251    MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
252    MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
253    MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
254    MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
255
256    buf[0] += a;
257    buf[1] += b;
258    buf[2] += c;
259    buf[3] += d;
260}
261