src/crypto/md4-internal.c - LeafOS-Project/android_external_wpa_supplicant_8 - Gitiles

 /*
  * MD4 hash implementation
  * Copyright (c) 2006, Jouni Malinen <j@w1.fi>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * Alternatively, this software may be distributed under the terms of BSD
  * license.
  *
  * See README and COPYING for more details.
  */

 #include "includes.h"

 #include "common.h"
 #include "crypto.h"

 #define	MD4_BLOCK_LENGTH		64
 #define	MD4_DIGEST_LENGTH		16

 typedef struct MD4Context {
 	u32 state[4];			/* state */
 	u64 count;			/* number of bits, mod 2^64 */
 	u8 buffer[MD4_BLOCK_LENGTH];	/* input buffer */
 } MD4_CTX;


 static void MD4Init(MD4_CTX *ctx);
 static void MD4Update(MD4_CTX *ctx, const unsigned char *input, size_t len);
 static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx);


 int md4_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
 {
 	MD4_CTX ctx;
 	size_t i;

 	MD4Init(&ctx);
 	for (i = 0; i < num_elem; i++)
 		MD4Update(&ctx, addr[i], len[i]);
 	MD4Final(mac, &ctx);
 	return 0;
 }


 /* ===== start - public domain MD4 implementation ===== */
 /*	$OpenBSD: md4.c,v 1.7 2005/08/08 08:05:35 espie Exp $	*/

 /*
  * This code implements the MD4 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.
  * Todd C. Miller modified the MD5 code to do MD4 based on RFC 1186.
  *
  * 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
  * MD4Context structure, pass it to MD4Init, call MD4Update as
  * needed on buffers full of bytes, and then call MD4Final, which
  * will fill a supplied 16-byte array with the digest.
  */

 #define	MD4_DIGEST_STRING_LENGTH	(MD4_DIGEST_LENGTH * 2 + 1)


 static void
 MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH]);

 #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 u8 PADDING[MD4_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 MD4 accumulation.
  * Set bit count to 0 and buffer to mysterious initialization constants.
  */
 static void MD4Init(MD4_CTX *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.
  */
 static void MD4Update(MD4_CTX *ctx, const unsigned char *input, size_t len)
 {
 	size_t have, need;

 	/* Check how many bytes we already have and how many more we need. */
 	have = (size_t)((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
 	need = MD4_BLOCK_LENGTH - have;

 	/* Update bitcount */
 	ctx->count += (u64)len << 3;

 	if (len >= need) {
 		if (have != 0) {
 			os_memcpy(ctx->buffer + have, input, need);
 			MD4Transform(ctx->state, ctx->buffer);
 			input += need;
 			len -= need;
 			have = 0;
 		}

 		/* Process data in MD4_BLOCK_LENGTH-byte chunks. */
 		while (len >= MD4_BLOCK_LENGTH) {
 			MD4Transform(ctx->state, input);
 			input += MD4_BLOCK_LENGTH;
 			len -= MD4_BLOCK_LENGTH;
 		}
 	}

 	/* Handle any remaining bytes of data. */
 	if (len != 0)
 		os_memcpy(ctx->buffer + have, input, len);
 }

 /*
  * Pad pad to 64-byte boundary with the bit pattern
  * 1 0* (64-bit count of bits processed, MSB-first)
  */
 static void MD4Pad(MD4_CTX *ctx)
 {
 	u8 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 = MD4_BLOCK_LENGTH -
 	    ((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
 	if (padlen < 1 + 8)
 		padlen += MD4_BLOCK_LENGTH;
 	MD4Update(ctx, PADDING, padlen - 8);		/* padlen - 8 <= 64 */
 	MD4Update(ctx, count, 8);
 }

 /*
  * Final wrapup--call MD4Pad, fill in digest and zero out ctx.
  */
 static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx)
 {
 	int i;

 	MD4Pad(ctx);
 	if (digest != NULL) {
 		for (i = 0; i < 4; i++)
 			PUT_32BIT_LE(digest + i * 4, ctx->state[i]);
 		os_memset(ctx, 0, sizeof(*ctx));
 	}
 }


 /* The three 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) ((x & y) | (x & z) | (y & z))
 #define F3(x, y, z) (x ^ y ^ z)

 /* This is the central step in the MD4 algorithm. */
 #define MD4STEP(f, w, x, y, z, data, s) \
 	( w += f(x, y, z) + data,  w = w<<s | w>>(32-s) )

 /*
  * The core of the MD4 algorithm, this alters an existing MD4 hash to
  * reflect the addition of 16 longwords of new data.  MD4Update blocks
  * the data and converts bytes into longwords for this routine.
  */
 static void
 MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH])
 {
 	u32 a, b, c, d, in[MD4_BLOCK_LENGTH / 4];

 #if BYTE_ORDER == LITTLE_ENDIAN
 	os_memcpy(in, block, sizeof(in));
 #else
 	for (a = 0; a < MD4_BLOCK_LENGTH / 4; a++) {
 		in[a] = (u32)(
 		    (u32)(block[a * 4 + 0]) |
 		    (u32)(block[a * 4 + 1]) <<  8 |
 		    (u32)(block[a * 4 + 2]) << 16 |
 		    (u32)(block[a * 4 + 3]) << 24);
 	}
 #endif

 	a = state[0];
 	b = state[1];
 	c = state[2];
 	d = state[3];

 	MD4STEP(F1, a, b, c, d, in[ 0],  3);
 	MD4STEP(F1, d, a, b, c, in[ 1],  7);
 	MD4STEP(F1, c, d, a, b, in[ 2], 11);
 	MD4STEP(F1, b, c, d, a, in[ 3], 19);
 	MD4STEP(F1, a, b, c, d, in[ 4],  3);
 	MD4STEP(F1, d, a, b, c, in[ 5],  7);
 	MD4STEP(F1, c, d, a, b, in[ 6], 11);
 	MD4STEP(F1, b, c, d, a, in[ 7], 19);
 	MD4STEP(F1, a, b, c, d, in[ 8],  3);
 	MD4STEP(F1, d, a, b, c, in[ 9],  7);
 	MD4STEP(F1, c, d, a, b, in[10], 11);
 	MD4STEP(F1, b, c, d, a, in[11], 19);
 	MD4STEP(F1, a, b, c, d, in[12],  3);
 	MD4STEP(F1, d, a, b, c, in[13],  7);
 	MD4STEP(F1, c, d, a, b, in[14], 11);
 	MD4STEP(F1, b, c, d, a, in[15], 19);

 	MD4STEP(F2, a, b, c, d, in[ 0] + 0x5a827999,  3);
 	MD4STEP(F2, d, a, b, c, in[ 4] + 0x5a827999,  5);
 	MD4STEP(F2, c, d, a, b, in[ 8] + 0x5a827999,  9);
 	MD4STEP(F2, b, c, d, a, in[12] + 0x5a827999, 13);
 	MD4STEP(F2, a, b, c, d, in[ 1] + 0x5a827999,  3);
 	MD4STEP(F2, d, a, b, c, in[ 5] + 0x5a827999,  5);
 	MD4STEP(F2, c, d, a, b, in[ 9] + 0x5a827999,  9);
 	MD4STEP(F2, b, c, d, a, in[13] + 0x5a827999, 13);
 	MD4STEP(F2, a, b, c, d, in[ 2] + 0x5a827999,  3);
 	MD4STEP(F2, d, a, b, c, in[ 6] + 0x5a827999,  5);
 	MD4STEP(F2, c, d, a, b, in[10] + 0x5a827999,  9);
 	MD4STEP(F2, b, c, d, a, in[14] + 0x5a827999, 13);
 	MD4STEP(F2, a, b, c, d, in[ 3] + 0x5a827999,  3);
 	MD4STEP(F2, d, a, b, c, in[ 7] + 0x5a827999,  5);
 	MD4STEP(F2, c, d, a, b, in[11] + 0x5a827999,  9);
 	MD4STEP(F2, b, c, d, a, in[15] + 0x5a827999, 13);

 	MD4STEP(F3, a, b, c, d, in[ 0] + 0x6ed9eba1,  3);
 	MD4STEP(F3, d, a, b, c, in[ 8] + 0x6ed9eba1,  9);
 	MD4STEP(F3, c, d, a, b, in[ 4] + 0x6ed9eba1, 11);
 	MD4STEP(F3, b, c, d, a, in[12] + 0x6ed9eba1, 15);
 	MD4STEP(F3, a, b, c, d, in[ 2] + 0x6ed9eba1,  3);
 	MD4STEP(F3, d, a, b, c, in[10] + 0x6ed9eba1,  9);
 	MD4STEP(F3, c, d, a, b, in[ 6] + 0x6ed9eba1, 11);
 	MD4STEP(F3, b, c, d, a, in[14] + 0x6ed9eba1, 15);
 	MD4STEP(F3, a, b, c, d, in[ 1] + 0x6ed9eba1,  3);
 	MD4STEP(F3, d, a, b, c, in[ 9] + 0x6ed9eba1,  9);
 	MD4STEP(F3, c, d, a, b, in[ 5] + 0x6ed9eba1, 11);
 	MD4STEP(F3, b, c, d, a, in[13] + 0x6ed9eba1, 15);
 	MD4STEP(F3, a, b, c, d, in[ 3] + 0x6ed9eba1,  3);
 	MD4STEP(F3, d, a, b, c, in[11] + 0x6ed9eba1,  9);
 	MD4STEP(F3, c, d, a, b, in[ 7] + 0x6ed9eba1, 11);
 	MD4STEP(F3, b, c, d, a, in[15] + 0x6ed9eba1, 15);

 	state[0] += a;
 	state[1] += b;
 	state[2] += c;
 	state[3] += d;
 }
 /* ===== end - public domain MD4 implementation ===== */
	/*
	* MD4 hash implementation
	* Copyright (c) 2006, Jouni Malinen <j@w1.fi>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* Alternatively, this software may be distributed under the terms of BSD
	* license.
	*
	* See README and COPYING for more details.
	*/

	#include "includes.h"

	#include "common.h"
	#include "crypto.h"

	#define MD4_BLOCK_LENGTH 64
	#define MD4_DIGEST_LENGTH 16

	typedef struct MD4Context {
	u32 state[4]; /* state */
	u64 count; /* number of bits, mod 2^64 */
	u8 buffer[MD4_BLOCK_LENGTH]; /* input buffer */
	} MD4_CTX;


	static void MD4Init(MD4_CTX *ctx);
	static void MD4Update(MD4_CTX ctx, const unsigned char input, size_t len);
	static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx);


	int md4_vector(size_t num_elem, const u8 addr[], const size_t len, u8 *mac)
	{
	MD4_CTX ctx;
	size_t i;

	MD4Init(&ctx);
	for (i = 0; i < num_elem; i++)
	MD4Update(&ctx, addr[i], len[i]);
	MD4Final(mac, &ctx);
	return 0;
	}


	/* ===== start - public domain MD4 implementation ===== */
	/* $OpenBSD: md4.c,v 1.7 2005/08/08 08:05:35 espie Exp $ */

	/*
	* This code implements the MD4 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.
	* Todd C. Miller modified the MD5 code to do MD4 based on RFC 1186.
	*
	* 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
	* MD4Context structure, pass it to MD4Init, call MD4Update as
	* needed on buffers full of bytes, and then call MD4Final, which
	* will fill a supplied 16-byte array with the digest.
	*/

	#define MD4_DIGEST_STRING_LENGTH (MD4_DIGEST_LENGTH * 2 + 1)


	static void
	MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH]);

	#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 u8 PADDING[MD4_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 MD4 accumulation.
	* Set bit count to 0 and buffer to mysterious initialization constants.
	*/
	static void MD4Init(MD4_CTX *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.
	*/
	static void MD4Update(MD4_CTX ctx, const unsigned char input, size_t len)
	{
	size_t have, need;

	/* Check how many bytes we already have and how many more we need. */
	have = (size_t)((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
	need = MD4_BLOCK_LENGTH - have;

	/* Update bitcount */
	ctx->count += (u64)len << 3;

	if (len >= need) {
	if (have != 0) {
	os_memcpy(ctx->buffer + have, input, need);
	MD4Transform(ctx->state, ctx->buffer);
	input += need;
	len -= need;
	have = 0;
	}

	/* Process data in MD4_BLOCK_LENGTH-byte chunks. */
	while (len >= MD4_BLOCK_LENGTH) {
	MD4Transform(ctx->state, input);
	input += MD4_BLOCK_LENGTH;
	len -= MD4_BLOCK_LENGTH;
	}
	}

	/* Handle any remaining bytes of data. */
	if (len != 0)
	os_memcpy(ctx->buffer + have, input, len);
	}

	/*
	* Pad pad to 64-byte boundary with the bit pattern
	* 1 0* (64-bit count of bits processed, MSB-first)
	*/
	static void MD4Pad(MD4_CTX *ctx)
	{
	u8 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 = MD4_BLOCK_LENGTH -
	((ctx->count >> 3) & (MD4_BLOCK_LENGTH - 1));
	if (padlen < 1 + 8)
	padlen += MD4_BLOCK_LENGTH;
	MD4Update(ctx, PADDING, padlen - 8); /* padlen - 8 <= 64 */
	MD4Update(ctx, count, 8);
	}

	/*
	* Final wrapup--call MD4Pad, fill in digest and zero out ctx.
	*/
	static void MD4Final(unsigned char digest[MD4_DIGEST_LENGTH], MD4_CTX *ctx)
	{
	int i;

	MD4Pad(ctx);
	if (digest != NULL) {
	for (i = 0; i < 4; i++)
	PUT_32BIT_LE(digest + i * 4, ctx->state[i]);
	os_memset(ctx, 0, sizeof(*ctx));
	}
	}


	/* The three 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) ((x & y) \| (x & z) \| (y & z))
	#define F3(x, y, z) (x ^ y ^ z)

	/* This is the central step in the MD4 algorithm. */
	#define MD4STEP(f, w, x, y, z, data, s) \
	( w += f(x, y, z) + data, w = w<<s \| w>>(32-s) )

	/*
	* The core of the MD4 algorithm, this alters an existing MD4 hash to
	* reflect the addition of 16 longwords of new data. MD4Update blocks
	* the data and converts bytes into longwords for this routine.
	*/
	static void
	MD4Transform(u32 state[4], const u8 block[MD4_BLOCK_LENGTH])
	{
	u32 a, b, c, d, in[MD4_BLOCK_LENGTH / 4];

	#if BYTE_ORDER == LITTLE_ENDIAN
	os_memcpy(in, block, sizeof(in));
	#else
	for (a = 0; a < MD4_BLOCK_LENGTH / 4; a++) {
	in[a] = (u32)(
	(u32)(block[a * 4 + 0]) \|
	(u32)(block[a * 4 + 1]) << 8 \|
	(u32)(block[a * 4 + 2]) << 16 \|
	(u32)(block[a * 4 + 3]) << 24);
	}
	#endif

	a = state[0];
	b = state[1];
	c = state[2];
	d = state[3];

	MD4STEP(F1, a, b, c, d, in[ 0], 3);
	MD4STEP(F1, d, a, b, c, in[ 1], 7);
	MD4STEP(F1, c, d, a, b, in[ 2], 11);
	MD4STEP(F1, b, c, d, a, in[ 3], 19);
	MD4STEP(F1, a, b, c, d, in[ 4], 3);
	MD4STEP(F1, d, a, b, c, in[ 5], 7);
	MD4STEP(F1, c, d, a, b, in[ 6], 11);
	MD4STEP(F1, b, c, d, a, in[ 7], 19);
	MD4STEP(F1, a, b, c, d, in[ 8], 3);
	MD4STEP(F1, d, a, b, c, in[ 9], 7);
	MD4STEP(F1, c, d, a, b, in[10], 11);
	MD4STEP(F1, b, c, d, a, in[11], 19);
	MD4STEP(F1, a, b, c, d, in[12], 3);
	MD4STEP(F1, d, a, b, c, in[13], 7);
	MD4STEP(F1, c, d, a, b, in[14], 11);
	MD4STEP(F1, b, c, d, a, in[15], 19);

	MD4STEP(F2, a, b, c, d, in[ 0] + 0x5a827999, 3);
	MD4STEP(F2, d, a, b, c, in[ 4] + 0x5a827999, 5);
	MD4STEP(F2, c, d, a, b, in[ 8] + 0x5a827999, 9);
	MD4STEP(F2, b, c, d, a, in[12] + 0x5a827999, 13);
	MD4STEP(F2, a, b, c, d, in[ 1] + 0x5a827999, 3);
	MD4STEP(F2, d, a, b, c, in[ 5] + 0x5a827999, 5);
	MD4STEP(F2, c, d, a, b, in[ 9] + 0x5a827999, 9);
	MD4STEP(F2, b, c, d, a, in[13] + 0x5a827999, 13);
	MD4STEP(F2, a, b, c, d, in[ 2] + 0x5a827999, 3);
	MD4STEP(F2, d, a, b, c, in[ 6] + 0x5a827999, 5);
	MD4STEP(F2, c, d, a, b, in[10] + 0x5a827999, 9);
	MD4STEP(F2, b, c, d, a, in[14] + 0x5a827999, 13);
	MD4STEP(F2, a, b, c, d, in[ 3] + 0x5a827999, 3);
	MD4STEP(F2, d, a, b, c, in[ 7] + 0x5a827999, 5);
	MD4STEP(F2, c, d, a, b, in[11] + 0x5a827999, 9);
	MD4STEP(F2, b, c, d, a, in[15] + 0x5a827999, 13);

	MD4STEP(F3, a, b, c, d, in[ 0] + 0x6ed9eba1, 3);
	MD4STEP(F3, d, a, b, c, in[ 8] + 0x6ed9eba1, 9);
	MD4STEP(F3, c, d, a, b, in[ 4] + 0x6ed9eba1, 11);
	MD4STEP(F3, b, c, d, a, in[12] + 0x6ed9eba1, 15);
	MD4STEP(F3, a, b, c, d, in[ 2] + 0x6ed9eba1, 3);
	MD4STEP(F3, d, a, b, c, in[10] + 0x6ed9eba1, 9);
	MD4STEP(F3, c, d, a, b, in[ 6] + 0x6ed9eba1, 11);
	MD4STEP(F3, b, c, d, a, in[14] + 0x6ed9eba1, 15);
	MD4STEP(F3, a, b, c, d, in[ 1] + 0x6ed9eba1, 3);
	MD4STEP(F3, d, a, b, c, in[ 9] + 0x6ed9eba1, 9);
	MD4STEP(F3, c, d, a, b, in[ 5] + 0x6ed9eba1, 11);
	MD4STEP(F3, b, c, d, a, in[13] + 0x6ed9eba1, 15);
	MD4STEP(F3, a, b, c, d, in[ 3] + 0x6ed9eba1, 3);
	MD4STEP(F3, d, a, b, c, in[11] + 0x6ed9eba1, 9);
	MD4STEP(F3, c, d, a, b, in[ 7] + 0x6ed9eba1, 11);
	MD4STEP(F3, b, c, d, a, in[15] + 0x6ed9eba1, 15);

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	}
	/* ===== end - public domain MD4 implementation ===== */