/* * FILE:    hmac.c * AUTHORS: Colin Perkins * * HMAC message authentication (RFC2104) *  * Copyright (c) 1998-2000 University College London * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, is permitted provided that the following conditions  * are met: * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright *    notice, this list of conditions and the following disclaimer in the *    documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software *    must display the following acknowledgement: *      This product includes software developed by the Computer Science *      Department at University College London * 4. Neither the name of the University nor of the Department may be used *    to endorse or promote products derived from this software without *    specific prior written permission. * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */#include "config_unix.h"#include "config_win32.h"#include "md5.h"#include "hmac.h"/** * hmac_md5: * @data: pointer to data stream. * @data_len: length of data stream in bytes. * @key: pointer to authentication key. * @key_len: length of authentication key in bytes. * @digest: digest to be filled in. *  * Computes MD5 @digest of @data using key @key.  *  **/void hmac_md5(unsigned char   *data,	   	      int              data_len,   	      unsigned char   *key, 	   	      int              key_len,	   	      unsigned char    digest[16]) {        MD5_CTX       context;        unsigned char k_ipad[65];    /* inner padding - key XORd with ipad */        unsigned char k_opad[65];    /* outer padding - key XORd with opad */        unsigned char tk[16];        int           i;        /* If key is longer than 64 bytes reset it to key=MD5(key) */        if (key_len > 64) {                MD5_CTX      tctx;                MD5Init(&tctx);                MD5Update(&tctx, key, key_len);                MD5Final(tk, &tctx);                key     = tk;                key_len = 16;        }        /*         * The HMAC_MD5 transform looks like:         *         * MD5(K XOR opad, MD5(K XOR ipad, data))         *         * where K is an n byte key         * ipad is the byte 0x36 repeated 64 times         * opad is the byte 0x5c repeated 64 times         * and text is the data being protected         */        /* Start out by storing key in pads */        memset(k_ipad, 0, sizeof(k_ipad));        memset(k_opad, 0, sizeof(k_opad));        memcpy(k_ipad, key, key_len);        memcpy(k_opad, key, key_len);        /* XOR key with ipad and opad values */        for (i=0; i<64; i++) {                k_ipad[i] ^= 0x36;                k_opad[i] ^= 0x5c;        }        /*         * perform inner MD5         */        MD5Init(&context);                   /* init context for 1st pass */        MD5Update(&context, k_ipad, 64);     /* start with inner pad      */        MD5Update(&context, data, data_len); /* then text of datagram     */        MD5Final(digest, &context);          /* finish up 1st pass        */        /*         * perform outer MD5         */        MD5Init(&context);                   /* init context for 2nd pass */        MD5Update(&context, k_opad, 64);     /* start with outer pad      */        MD5Update(&context, digest, 16);     /* then results of 1st hash  */        MD5Final(digest, &context);          /* finish up 2nd pass        */}/* * Test Vectors (Trailing '\0' of a character string not included in test): *  * key =         0x0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b * key_len =     16 bytes * data =        "Hi There" * data_len =    8  bytes * digest =      0x9294727a3638bb1c13f48ef8158bfc9d * * key =         "Jefe" * data =        "what do ya want for nothing?" * data_len =    28 bytes * digest =      0x750c783e6ab0b503eaa86e310a5db738 * * key =         0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA * key_len       16 bytes * data =        0xDDDDDDDDDDDDDDDDDDDD... *               ..DDDDDDDDDDDDDDDDDDDD... *               ..DDDDDDDDDDDDDDDDDDDD... *               ..DDDDDDDDDDDDDDDDDDDD... *               ..DDDDDDDDDDDDDDDDDDDD * data_len =    50 bytes * digest =      0x56be34521d144c88dbb8c733f0e8b3f6 */#ifdef TEST_HMACint main(){	unsigned char	*key  = "Jefe";	unsigned char	*data = "what do ya want for nothing?";	unsigned char	 digest[16];	int		 i;	hmac_md5(data, 28, key, 4, digest);	for (i = 0; i < 16; i++) {		printf("%02x", digest[i]);	}	printf("\n");	return 0;}#endif