md5.c
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 /*	$OpenBSD: md5.c,v 1.7 2004/05/28 15:10:27 millert Exp $	*/
 
 /*
  * 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.
  *
  * To compute the message digest of a chunk of bytes, declare an
  * MD5Context structure, pass it to MD5Init, call MD5Update as
  * needed on buffers full of bytes, and then call MD5Final, which
  * will fill a supplied 16-byte array with the digest.
1d0661db
  */
 
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 #include <sys/types.h>
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 #include <string.h>
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 #include "md5.h"
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 #define PUT_64BIT_LE(cp, value) do {					\
 	(cp)[7] = (value) >> 56;					\
 	(cp)[6] = (value) >> 48;					\
 	(cp)[5] = (value) >> 40;					\
 	(cp)[4] = (value) >> 32;					\
 	(cp)[3] = (value) >> 24;					\
 	(cp)[2] = (value) >> 16;					\
 	(cp)[1] = (value) >> 8;						\
 	(cp)[0] = (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 u_int8_t 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
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 };
 
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 /*
  * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
  * initialization constants.
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  */
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 void
 MD5Init(MD5_CTX *ctx)
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 {
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 	ctx->count = 0;
 	ctx->state[0] = 0x67452301;
 	ctx->state[1] = 0xefcdab89;
 	ctx->state[2] = 0x98badcfe;
 	ctx->state[3] = 0x10325476;
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 }
 
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 /*
  * Update context to reflect the concatenation of another buffer full
  * of bytes.
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  */
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 void
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 U_MD5Update(MD5_CTX *ctx, const unsigned char *input, size_t len)
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 {
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 	size_t have, need;
 
 	/* Check how many bytes we already have and how many more we need. */
 	have = (size_t)((ctx->count >> 3) & (MD5_BLOCK_LENGTH - 1));
 	need = MD5_BLOCK_LENGTH - have;
 
 	/* Update bitcount */
 	ctx->count += (u_int64_t)len << 3;
 
 	if (len >= need) {
 		if (have != 0) {
 			memcpy(ctx->buffer + have, input, need);
 			MD5Transform(ctx->state, ctx->buffer);
 			input += need;
 			len -= need;
 			have = 0;
 		}
 
 		/* Process data in MD5_BLOCK_LENGTH-byte chunks. */
 		while (len >= MD5_BLOCK_LENGTH) {
 			MD5Transform(ctx->state, input);
 			input += MD5_BLOCK_LENGTH;
 			len -= MD5_BLOCK_LENGTH;
 		}
 	}
 
 	/* Handle any remaining bytes of data. */
 	if (len != 0)
 		memcpy(ctx->buffer + have, input, len);
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 }
 
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 /*
  * Pad pad to 64-byte boundary with the bit pattern
  * 1 0* (64-bit count of bits processed, MSB-first)
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  */
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 void
 MD5Pad(MD5_CTX *ctx)
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 {
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 	u_int8_t count[8];
 	size_t 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;
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 	U_MD5Update(ctx, PADDING, padlen - 8);		/* padlen - 8 <= 64 */
 	U_MD5Update(ctx, count, 8);
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 }
 
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 /*
  * Final wrapup--call MD5Pad, fill in digest and zero out ctx.
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  */
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 void
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 U_MD5Final(unsigned char digest[MD5_DIGEST_LENGTH], MD5_CTX *ctx)
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 {
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 	int i;
 
 	MD5Pad(ctx);
 	if (digest != NULL) {
 		for (i = 0; i < 4; i++)
 			PUT_32BIT_LE(digest + i * 4, ctx->state[i]);
 		memset(ctx, 0, sizeof(*ctx));
 	}
 }
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 /* The four core functions - F1 is optimized somewhat */
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 /* #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))
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 /* 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 )
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 /*
  * 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.
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  */
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 void
 MD5Transform(u_int32_t state[4], const u_int8_t block[MD5_BLOCK_LENGTH])
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 {
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 	u_int32_t a, b, c, d, in[MD5_BLOCK_LENGTH / 4];
 
 #ifndef WORDS_BIGENDIAN
 	memcpy(in, block, sizeof(in));
 #else
 	for (a = 0; a < MD5_BLOCK_LENGTH / 4; a++) {
 		in[a] = (u_int32_t)(
 		    (u_int32_t)(block[a * 4 + 0]) |
 		    (u_int32_t)(block[a * 4 + 1]) <<  8 |
 		    (u_int32_t)(block[a * 4 + 2]) << 16 |
 		    (u_int32_t)(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;
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 }