Files
zTC1/mico-os/libraries/utilities/SecurityUtils.c

57 lines
2.4 KiB
C

/**
******************************************************************************
* @file SecurityUtils.C
* @author William Xu
* @version V1.0.0
* @date 05-May-2014
* @brief This header contains function that aid in security on the platform.
******************************************************************************
*
* The MIT License
* Copyright (c) 2014 MXCHIP Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is furnished
* to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
* IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
******************************************************************************
*/
#include "SecurityUtils.h"
//===========================================================================================================================
// memcmp_constant_time
//
// Compares memory so that the time it takes does not depend on the data being compared.
// This is needed to avoid certain timing attacks in cryptographic software.
//===========================================================================================================================
int memcmp_constant_time( const void *inA, const void *inB, size_t inLen )
{
const uint8_t * const a = (const uint8_t *) inA;
const uint8_t * const b = (const uint8_t *) inB;
int result = 0;
size_t i;
for( i = 0; i < inLen; ++i )
{
result |= ( a[ i ] ^ b[ i ] );
}
return( result );
}