src/lib/crypto/hmac.c

   1 /*
   2  * Copyright (c) 2007, Cameron Rich
   3  *
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are met:
   8  *
   9  * * Redistributions of source code must retain the above copyright notice,
  10  *   this list of conditions and the following disclaimer.
  11  * * Redistributions in binary form must reproduce the above copyright notice,
  12  *   this list of conditions and the following disclaimer in the documentation
  13  *   and/or other materials provided with the distribution.
  14  * * Neither the name of the axTLS project nor the names of its contributors
  15  *   may be used to endorse or promote products derived from this software
  16  *   without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  22  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  23  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  24  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  25  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  26  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  27  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  28  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 /**
  32  * HMAC implementation - This code was originally taken from RFC2104
  33  * See http://www.ietf.org/rfc/rfc2104.txt and
  34  * http://www.faqs.org/rfcs/rfc2202.html
  35  */
  36
  37 #include <string.h>
  38 #include "os_port.h"
  39 #include "crypto.h"
  40
  41 /**
  42  * Perform HMAC-MD5
  43  * NOTE: does not handle keys larger than the block size.
  44  */
  45 void hmac_md5(const uint8_t *msg, int length, const uint8_t *key,
  46         int key_len, uint8_t *digest)
  47 {
  48     MD5_CTX context;
  49     uint8_t k_ipad[64];
  50     uint8_t k_opad[64];
  51     int i;
  52
  53     memset(k_ipad, 0, sizeof k_ipad);
  54     memset(k_opad, 0, sizeof k_opad);
  55     memcpy(k_ipad, key, key_len);
  56     memcpy(k_opad, key, key_len);
  57
  58     for (i = 0; i < 64; i++)
  59     {
  60         k_ipad[i] ^= 0x36;
  61         k_opad[i] ^= 0x5c;
  62     }
  63
  64     MD5_Init(&context);
  65     MD5_Update(&context, k_ipad, 64);
  66     MD5_Update(&context, msg, length);
  67     MD5_Final(digest, &context);
  68     MD5_Init(&context);
  69     MD5_Update(&context, k_opad, 64);
  70     MD5_Update(&context, digest, MD5_SIZE);
  71     MD5_Final(digest, &context);
  72 }
  73
  74 /**
  75  * Perform HMAC-SHA1
  76  * NOTE: does not handle keys larger than the block size.
  77  */
  78 void hmac_sha1(const uint8_t *msg, int length, const uint8_t *key,
  79         int key_len, uint8_t *digest)
  80 {
  81     SHA1_CTX context;
  82     uint8_t k_ipad[64];
  83     uint8_t k_opad[64];
  84     int i;
  85
  86     memset(k_ipad, 0, sizeof k_ipad);
  87     memset(k_opad, 0, sizeof k_opad);
  88     memcpy(k_ipad, key, key_len);
  89     memcpy(k_opad, key, key_len);
  90
  91     for (i = 0; i < 64; i++)
  92     {
  93         k_ipad[i] ^= 0x36;
  94         k_opad[i] ^= 0x5c;
  95     }
  96
  97     SHA1_Init(&context);
  98     SHA1_Update(&context, k_ipad, 64);
  99     SHA1_Update(&context, msg, length);
 100     SHA1_Final(digest, &context);
 101     SHA1_Init(&context);
 102     SHA1_Update(&context, k_opad, 64);
 103     SHA1_Update(&context, digest, SHA1_SIZE);
 104     SHA1_Final(digest, &context);
 105 }