OVMS3/OVMS.V3/components/crypto/crypt_hmac.cpp

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/*
* Copyright (c) 2007, Cameron Rich
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of the axTLS project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS 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 COPYRIGHT OWNER 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.
*/
/**
* HMAC implementation - This code was originally taken from RFC2104
*/
#include <string.h>
#include "crypt_md5.h"
#include "crypt_hmac.h"
/**
* Perform HMAC-MD5
*/
void hmac_md5(const uint8_t *msg, int length, const uint8_t *key,
int key_len, uint8_t *digest)
{
OVMS_MD5_CTX context;
int i;
uint8_t k_ipad[64];
uint8_t k_opad[64];
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);
for (i = 0; i < 64; i++)
{
k_ipad[i] ^= 0x36;
k_opad[i] ^= 0x5c;
}
OVMS_MD5_Init(&context);
OVMS_MD5_Update(&context, k_ipad, 64);
OVMS_MD5_Update(&context, msg, length);
OVMS_MD5_Final(digest,&context);
OVMS_MD5_Init(&context);
OVMS_MD5_Update(&context, k_opad, 64);
OVMS_MD5_Update(&context, digest, 16);
OVMS_MD5_Final(digest,&context);
}