Реализация алгоритма MD5 на языке C
Если вы хотите прочитать про основы алгоритма MD5, то вам стоит почитать статью: Алгоритм хэш-функции MD5. Здесь мы рассмотрим реализацию алгоритма MD5 на языке C/C++.
Исходный файл можно скачать здесь.
#include "md5.h"
#include <string.h>
main()
{
static const char *const test[7] = {
"", /*d41d8cd98f00b204e9800998ecf8427e*/
"945399884.61923487334tuvga",/*0cc175b9c0f1b6a831c399e269772661*/
"abc", /*900150983cd24fb0d6963f7d28e17f72*/
"message digest", /*f96b697d7cb7938d525a2f31aaf161d0*/
"abcdefghijklmnopqrstuvwxyz", /*c3fcd3d76192e4007dfb496cca67e13b*/
};
int i;
for (i = 0; i < 7; ++i) {
md5_state_t state;
md5_byte_t digest[16];
int di;
md5_init(&state);
md5_append(&state, (const md5_byte_t *)test[i], strlen(test[i]));
md5_finish(&state, digest);
printf("MD5 (\"%s\") = ", test[i]);
for (di = 0; di < 16; ++di)
printf("%02x", digest[di]);
printf("\n");
}
return 0;
}
#define T1 0xd76aa478
#define T2 0xe8c7b756
#define T3 0x242070db
#define T4 0xc1bdceee
#define T5 0xf57c0faf
#define T6 0x4787c62a
#define T7 0xa8304613
#define T8 0xfd469501
#define T9 0x698098d8
#define T10 0x8b44f7af
#define T11 0xffff5bb1
#define T12 0x895cd7be
#define T13 0x6b901122
#define T14 0xfd987193
#define T15 0xa679438e
#define T16 0x49b40821
#define T17 0xf61e2562
#define T18 0xc040b340
#define T19 0x265e5a51
#define T20 0xe9b6c7aa
#define T21 0xd62f105d
#define T22 0x02441453
#define T23 0xd8a1e681
#define T24 0xe7d3fbc8
#define T25 0x21e1cde6
#define T26 0xc33707d6
#define T27 0xf4d50d87
#define T28 0x455a14ed
#define T29 0xa9e3e905
#define T30 0xfcefa3f8
#define T31 0x676f02d9
#define T32 0x8d2a4c8a
#define T33 0xfffa3942
#define T34 0x8771f681
#define T35 0x6d9d6122
#define T36 0xfde5380c
#define T37 0xa4beea44
#define T38 0x4bdecfa9
#define T39 0xf6bb4b60
#define T40 0xbebfbc70
#define T41 0x289b7ec6
#define T42 0xeaa127fa
#define T43 0xd4ef3085
#define T44 0x04881d05
#define T45 0xd9d4d039
#define T46 0xe6db99e5
#define T47 0x1fa27cf8
#define T48 0xc4ac5665
#define T49 0xf4292244
#define T50 0x432aff97
#define T51 0xab9423a7
#define T52 0xfc93a039
#define T53 0x655b59c3
#define T54 0x8f0ccc92
#define T55 0xffeff47d
#define T56 0x85845dd1
#define T57 0x6fa87e4f
#define T58 0xfe2ce6e0
#define T59 0xa3014314
#define T60 0x4e0811a1
#define T61 0xf7537e82
#define T62 0xbd3af235
#define T63 0x2ad7d2bb
#define T64 0xeb86d391
static void
md5_process(md5_state_t *pms, const md5_byte_t *data /*[64]*/)
{
md5_word_t
a = pms->abcd[0], b = pms->abcd[1],
c = pms->abcd[2]<
/FONT>, d = pms->abcd[3];
md5_word_t t;
#ifndef ARCH_IS_BIG_ENDIAN
# define ARCH_IS_BIG_ENDIAN 1 /* slower, default implementation */
#endif
#if ARCH_IS_BIG_ENDIAN
/*
* On big-endian machines, we must arrange the bytes in the right
* order. (This also works on machines of unknown byte order.)
*/
md5_word_t X[16];
const md5_byte_t *xp = data;
int i;
for (i = 0; i < 16; ++i, xp += 4)
X[i] = xp[0] + (xp[1] << 8) + (xp[2] << 16) + (xp[3] << 24);
#else /* !ARCH_IS_BIG_ENDIAN */
/*
* On little-endian machines, we can process properly aligned data
* without copying it.
*/
md5_word_t xbuf[16];
const md5_word_t *X;
if (!((data - (const md5_byte_t *)0) & 3)) {
/* data are properly aligned */
X = (const md5_word_t *)data;
} else {
/* not aligned */
memcpy(xbuf, data, 64);
X = xbuf;
}
#endif
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
/* Round 1. */
/* Let [abcd k s i] denote the operation
a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
#define F(x, y, z) (((x) & (y)) | (~(x) & (z)))
#define SET(a, b, c, d, k, s, Ti)\
t = a + F(b,c,d) + X[k] + Ti;\
a = ROTATE_LEFT(t, s) + b
/* Do the following 16 operations. */
SET(a, b, c, d, 0, 7, T1);
SET(d, a, b, c, 1, 12, T2);
SET(c, d, a, b, 2, 17, T3);
SET(b, c, d, a, 3, 22, T4);
SET(a, b, c, d, 4, 7, T5);
SET(d, a, b, c, 5, 12, T6);
SET(c, d, a, b, 6, 17, T7);
SET(b, c, d, a, 7, 22, T8);
SET(a, b, c, d, 8, 7, T9);
SET(d,<;/FONT> a, b, c, 9, 12, T10);
SET(c, d, a, b, 10, 17, T11);
SET(b, c, d, a, 11, 22, T12);
SET(a, b, c, d, 12, 7, T13);
SET(d, a, b, c, 13, 12, T14);
SET(c, d<;;FONT COLOR=BLUE SIZE=+1>, a, b, 14, 17, T15);
SET(b, c, d, a, 15, 22, T16);
#undef SET
/* Round 2. */
/* Let [abcd k s i] denote the operation
a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
#define G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
#define SET(a, b, c, d, k, s, Ti)\
t = a + G(b,c,d) + X[k] + Ti;\
a = ROTATE_LEFT(t, s) + b
/* Do the following 16 operations. */
SET(a, b, c, d, 1, 5, T17);
SET(d, a, b, c, 6, 9, T18);
SET(c, d, a, b, 11, 14, T19);
SET(b, c, d, a, 0, 20, T20);
SET(a, b, c, d, 5, 5, T21);
SET(d, a, b, c, 10, 9, T22);
SET(c, d, a, b, 15, 14, T23);
SET(b, c, d, a, 4, 20, T24);
SET(a, b, c, d, 9, 5, T25);
SET(d, a, b, c, 14, 9, T26);
SET(c, d, a, b, 3, 14, T27);
SET(b, c, d, a, 8, 20, T28);
SET(a, b, c, d, 13, 5, T29);
SET(d, a, b, c, 2, 9, T30);
SET(c, d, a, b, 7, 14, T31);
SET(b, c, d, a, 12, 20, T32);
#undef SET
/* Round 3. */
/* Let [abcd k s t] denote the operation
a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define SET(a, b, c, d, k, s, Ti)\
t = a + H(b,c,d) + X[k] + Ti;\
a = ROTATE_LEFT(t, s) + b
/* Do the following 16 operations. */
SET(a, b, c, d, 5, 4, T33);
SET(d, a, b, c, 8, 11, T34);
SET(c, d, a, b, 11, 16, T35);
SET(b, c, d, a, 14, 23, T36);
SET(a, b, c, d, 1, 4, T37);
SET(d, a, b, c, 4, 11, T38);
SET(c, d, a, b, 7, 16, T39);
SET(b, c, d, a, 10, 23, T40);
SET(a, b, c, d, 13, 4, T41);
SET(d, a, b, c, 0, 11, T42);
SET(c, d, a, b, 3, 16, T43);
SET(b, c, d, a, 6, 23, T44);
SET(a, b, c, d, 9, 4, T45);
SET(d, a, b, c, 12, 11, T46);
SET(c, d, a, b, 15, 16, T47);
SET(b, c<;B>, d, a, 2, 23, T48);
#undef SET
/* Round 4. */
/* Let [abcd k s t] denote the operation
a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
#define I(x, y, z) ((y) ^ ((x) | ~(z)))
#define SET(a, b, c, d, k, s, Ti)\
t = a + I(b,c,d) + X[k] + Ti;\
a = ROTATE_LEFT(t, s) + b
/* Do the following 16 operations. */
SET(a, b, c, d, 0, 6, T49);
SET(d, a,; b, c, 7, 10, T50);
SET(c, d, a, b, 14, 15, T51);
SET(b, c, d, a, 5, 21, T52);
SET(a, b, c, d, 12, 6, T53);
SET(d, a, b, c, 3, 10, T54);
SET(c, d, a, b, 10, 15, T55);
SET(b, c, d, a, 1, 21, T56);
SET(a, b, c, d, 8, 6, T57);
SET(d, a, b, c, 15, 10, T58);
SET(c, d, a, b, 6, 15, T59);
SET(b, c, d, a, 13, 21, T60);
SET(a, b, c, d, 4,
6, T61);
SET(d, a, b, c, 11, 10, T62);
SET(c, d, a, b, 2, 15, T63);
SET(b, c, d, a, 9, 21, T64);
#undef SET
/* Then perform the following additions. (That is increment each
of the four registers by the value it had before this block
was started.) */
pms->abcd[0] += a;
pms->abcd[1] += b;
pms->abcd[2] += c;
pms->abcd[3] += d;
}
void
md5_init(md5_state_t *pms)
{
pms->count[0] = pms->count[1] = 0;
pms->abcd[0] = 0x67452301;
pms->abcd[1] = 0xefcdab89;
pms->abcd[2] = 0x98badcfe;
pms->abcd[3] = 0x10325476;
}
void
md5_append(md5_state_t *pms, const md5_byte_t *data, int nbytes)
{
const md5_byte_t *p = data;
int left = nbytes;
int offset = (pms->count[0] >> 3) & 63;
md5_word_t nbits = (md5_word_t)(nbytes << 3);
if (nbytes <= 0)
return;
/* Update the message length. */
pms->count[1] += nbytes >> 29;
pms->count[0] += nbits;
if (pms->count[0] < nbits)
pms->count[1]
++;
/* Process an initial partial block. */
if (offset) {
int copy = (offset + nbytes > 64 ? 64 - offset : nbytes);
memcpy(pms->buf + offset, p, copy);
if (offset + copy < 64)
return;
p += copy;
left -= copy;
md5_process(pms, pms->buf);
}
/* Process full blocks. */
for (; left >= 64; p += 64, left -= 64)
md5_process(pms, p);
/* Process a final partial block. */
if (left)
memcpy(pms->buf, p, left);
}
void
md5_finish(md5_state_t *pms, md5_byte_t digest[16])
{
static const md5_byte_t pad[64] = {
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
B>, 0
/FONT>, 0
};
md5_byte_t data[8];
int i;
/* Save the length before padding. */
for (i = 0; i < 8; ++i)
data[i] = (md5_byte_t)(pms->count[i >> 2] >> ((i & 3) << 3));
/* Pad to 56 bytes mod 64. */
md5_append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
/* Append the length. */
md5_append(pms, data, 8);
for (i = 0; i < 16; ++i)
digest[i] = (md5_byte_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
}