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md5.c
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md5.c
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/* ---------------------------------------------------------------- *\
file: md5.c (taken from alock)
about: implements md5-checksumming
author: m. gumz <[email protected]>
license: based on: openbsd md5.c/h
This code implements the MD5 message-digest algorithm.
The algorithm is due to Ron Rivest. This code was
written by Colin Plumb in 1993, no copyright is claimed.
This code is in the public domain; do with it what you wish.
Equivalent code is available from RSA Data Security, Inc.
This code has been tested against that, and is equivalent,
except that you don't need to include two pages of legalese
with every copy.
\* ---------------------------------------------------------------- */
#include "md5.h"
#include "djb/byte.h" // byte_copy, byte_zero
/*------------------------------------------------------------------*\
\*------------------------------------------------------------------*/
#define PUT_64BIT_LE(cp, value) do { \
(cp)[7] = (unsigned char)((value) >> 56); \
(cp)[6] = (unsigned char)((value) >> 48); \
(cp)[5] = (unsigned char)((value) >> 40); \
(cp)[4] = (unsigned char)((value) >> 32); \
(cp)[3] = (unsigned char)((value) >> 24); \
(cp)[2] = (unsigned char)((value) >> 16); \
(cp)[1] = (unsigned char)((value) >> 8); \
(cp)[0] = (unsigned char)(value); } while (0)
#define PUT_32BIT_LE(cp, value) do { \
(cp)[3] = (value) >> 24; \
(cp)[2] = (value) >> 16; \
(cp)[1] = (value) >> 8; \
(cp)[0] = (value); } while (0)
static unsigned char PADDING[MD5_BLOCK_LENGTH] = {
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, 0, 0
};
/*------------------------------------------------------------------*\
Start MD5 accumulation. Set bit count to 0 and buffer to
mysterious initialization constants.
\*------------------------------------------------------------------*/
void md5_init(md5Context* ctx) {
ctx->count = 0;
ctx->state[0] = 0x67452301;
ctx->state[1] = 0xefcdab89;
ctx->state[2] = 0x98badcfe;
ctx->state[3] = 0x10325476;
}
/*------------------------------------------------------------------*\
Update context to reflect the concatenation of another buffer
full of bytes.
\*------------------------------------------------------------------*/
void md5_update(md5Context* ctx, const unsigned char input[], size_t len) {
unsigned int have, need;
/* Check how many bytes we already have and how many more we need. */
have = (unsigned int)((ctx->count >> 3) & (MD5_BLOCK_LENGTH - 1));
need = MD5_BLOCK_LENGTH - have;
/* Update bitcount */
ctx->count += ((unsigned long long)len) << 3;
if (len >= need) {
if (have != 0) {
byte_copy(ctx->buffer + have, need, input);
md5_transform(ctx->state, ctx->buffer);
input += need;
len -= need;
have = 0;
}
/* Process data in MD5_BLOCK_LENGTH-byte chunks. */
while (len >= MD5_BLOCK_LENGTH) {
md5_transform(ctx->state, input);
input += MD5_BLOCK_LENGTH;
len -= MD5_BLOCK_LENGTH;
}
}
/* Handle any remaining bytes of data. */
if (len != 0) {
byte_copy(ctx->buffer + have, len, input);
}
}
/*------------------------------------------------------------------*\
Pad pad to 64-byte boundary with the bit pattern
1 0* (64-bit count of bits processed, MSB-first)
\*------------------------------------------------------------------*/
void md5_pad(md5Context *ctx) {
unsigned char count[8];
unsigned int padlen;
/* Convert count to 8 bytes in little endian order. */
PUT_64BIT_LE(count, ctx->count);
/* Pad out to 56 mod 64. */
padlen = MD5_BLOCK_LENGTH -
((ctx->count >> 3) & (MD5_BLOCK_LENGTH - 1));
if (padlen < 1 + 8)
padlen += MD5_BLOCK_LENGTH;
md5_update(ctx, PADDING, padlen - 8); /* padlen - 8 <= 64 */
md5_update(ctx, count, 8);
}
/*------------------------------------------------------------------*\
Final wrapup--call MD5Pad, fill in digest and zero out ctx.
\*------------------------------------------------------------------*/
void md5_final(unsigned char digest[MD5_DIGEST_LENGTH], md5Context *ctx) {
unsigned int i;
md5_pad(ctx);
if (digest != 0) {
for (i = 0; i < 4; i++) {
PUT_32BIT_LE(digest + i * 4, ctx->state[i]);
}
byte_zero((char*)ctx, sizeof(*ctx));
}
}
/* The four core functions - F1 is optimized somewhat */
/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))
/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
/*------------------------------------------------------------------*\
The core of the MD5 algorithm, this alters an existing MD5 hash to
reflect the addition of 16 longwords of new data. MD5Update blocks
the data and converts bytes into longwords for this routine.
\*------------------------------------------------------------------*/
void md5_transform(unsigned int state[4], const unsigned char block[MD5_BLOCK_LENGTH]) {
unsigned int a, b, c, d, in[MD5_BLOCK_LENGTH / 4];
#if BYTE_ORDER == LITTLE_ENDIAN
byte_copy(in, sizeof(in), block);
#else
for (a = 0; a < MD5_BLOCK_LENGTH / 4; a++) {
in[a] = (unsigned int)(
(unsigned int)(block[a * 4 + 0]) |
(unsigned int)(block[a * 4 + 1]) << 8 |
(unsigned int)(block[a * 4 + 2]) << 16 |
(unsigned int)(block[a * 4 + 3]) << 24);
}
#endif
a = state[0];
b = state[1];
c = state[2];
d = state[3];
MD5STEP(F1, a, b, c, d, in[ 0] + 0xd76aa478, 7);
MD5STEP(F1, d, a, b, c, in[ 1] + 0xe8c7b756, 12);
MD5STEP(F1, c, d, a, b, in[ 2] + 0x242070db, 17);
MD5STEP(F1, b, c, d, a, in[ 3] + 0xc1bdceee, 22);
MD5STEP(F1, a, b, c, d, in[ 4] + 0xf57c0faf, 7);
MD5STEP(F1, d, a, b, c, in[ 5] + 0x4787c62a, 12);
MD5STEP(F1, c, d, a, b, in[ 6] + 0xa8304613, 17);
MD5STEP(F1, b, c, d, a, in[ 7] + 0xfd469501, 22);
MD5STEP(F1, a, b, c, d, in[ 8] + 0x698098d8, 7);
MD5STEP(F1, d, a, b, c, in[ 9] + 0x8b44f7af, 12);
MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
MD5STEP(F2, a, b, c, d, in[ 1] + 0xf61e2562, 5);
MD5STEP(F2, d, a, b, c, in[ 6] + 0xc040b340, 9);
MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
MD5STEP(F2, b, c, d, a, in[ 0] + 0xe9b6c7aa, 20);
MD5STEP(F2, a, b, c, d, in[ 5] + 0xd62f105d, 5);
MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
MD5STEP(F2, b, c, d, a, in[ 4] + 0xe7d3fbc8, 20);
MD5STEP(F2, a, b, c, d, in[ 9] + 0x21e1cde6, 5);
MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
MD5STEP(F2, c, d, a, b, in[ 3] + 0xf4d50d87, 14);
MD5STEP(F2, b, c, d, a, in[ 8] + 0x455a14ed, 20);
MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
MD5STEP(F2, d, a, b, c, in[ 2] + 0xfcefa3f8, 9);
MD5STEP(F2, c, d, a, b, in[ 7] + 0x676f02d9, 14);
MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
MD5STEP(F3, a, b, c, d, in[ 5] + 0xfffa3942, 4);
MD5STEP(F3, d, a, b, c, in[ 8] + 0x8771f681, 11);
MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
MD5STEP(F3, a, b, c, d, in[ 1] + 0xa4beea44, 4);
MD5STEP(F3, d, a, b, c, in[ 4] + 0x4bdecfa9, 11);
MD5STEP(F3, c, d, a, b, in[ 7] + 0xf6bb4b60, 16);
MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
MD5STEP(F3, d, a, b, c, in[ 0] + 0xeaa127fa, 11);
MD5STEP(F3, c, d, a, b, in[ 3] + 0xd4ef3085, 16);
MD5STEP(F3, b, c, d, a, in[ 6] + 0x04881d05, 23);
MD5STEP(F3, a, b, c, d, in[ 9] + 0xd9d4d039, 4);
MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
MD5STEP(F3, b, c, d, a, in[2 ] + 0xc4ac5665, 23);
MD5STEP(F4, a, b, c, d, in[ 0] + 0xf4292244, 6);
MD5STEP(F4, d, a, b, c, in[7 ] + 0x432aff97, 10);
MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
MD5STEP(F4, b, c, d, a, in[5 ] + 0xfc93a039, 21);
MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
MD5STEP(F4, d, a, b, c, in[3 ] + 0x8f0ccc92, 10);
MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
MD5STEP(F4, b, c, d, a, in[1 ] + 0x85845dd1, 21);
MD5STEP(F4, a, b, c, d, in[8 ] + 0x6fa87e4f, 6);
MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
MD5STEP(F4, c, d, a, b, in[6 ] + 0xa3014314, 15);
MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
MD5STEP(F4, a, b, c, d, in[4 ] + 0xf7537e82, 6);
MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
MD5STEP(F4, c, d, a, b, in[2 ] + 0x2ad7d2bb, 15);
MD5STEP(F4, b, c, d, a, in[9 ] + 0xeb86d391, 21);
state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;
}