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/* ----------------------------------------------------------------------------
* ATMEL Microcontroller Software Support
* ----------------------------------------------------------------------------
* Copyright (c) 2008, Atmel Corporation
*
* 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 disclaimer below.
*
* Atmel's name may not be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
* ----------------------------------------------------------------------------
*/
//------------------------------------------------------------------------------
/// \unit
///
/// !Purpose
///
/// Firmware encryption using AES reference implementation
///
/// !Usage
///
/// -# aes_ref_init: Initialize AES hardware
/// -# aes_ref_init_CBC: for the CBC mode
/// -# aes_ref_init_ECB: for the CTR mode
/// -# aes_ref_init_CTR: for the ECB mode
/// -# aes_ref_cleanup: Cleans up AES
/// -# aes_ref_decrypt: Decrypts a variable-length cipher text
/// -# aes_ref_decrypt_CBC: for CBC mode
/// -# aes_ref_decrypt_ECB: for ECB mode
/// -# aes_ref_decrypt_CTR: for CTR mode
//------------------------------------------------------------------------------
#ifndef BOOTLOADER_AES_REFERENCE_H
#define BOOTLOADER_AES_REFERENCE_H
//------------------------------------------------------------------------------
// Includes
//------------------------------------------------------------------------------
#include "config.h"
#if defined(USE_ENCRYPTION) && defined(ENCRYPTION_AES_REF)
//------------------------------------------------------------------------------
// Check configuration
//------------------------------------------------------------------------------
// Supported modes
#if !defined(ENCRYPTION_ECB) && \
!defined(ENCRYPTION_CBC) && \
!defined(ENCRYPTION_CTR)
#error No other mode than ECB, CBC & CTR are supported.
#endif
// Supported key length
#if (ENCRYPTION_KEY_LENGTH != 16) && \
(ENCRYPTION_KEY_LENGTH != 24) && \
(ENCRYPTION_KEY_LENGTH != 32)
#error Only key lengths of 128, 192 or 256 bits are supported.
#endif
// Supported block length
#if (ENCRYPTION_BLOCK_LENGTH != 16)
#error Only block length of 128 bits is supported.
#endif
//------------------------------------------------------------------------------
// Definitions
//------------------------------------------------------------------------------
#define BC (ENCRYPTION_BLOCK_LENGTH / 4)
#define SC ((BC - 4) >> 1)
#define KC (ENCRYPTION_KEY_LENGTH / 4)
#define t0f 0x000000FF & tf
#define t1f 0x0000FF00 & tf
#define t2f 0x00FF0000 & tf
#define t3f 0xFF000000 & tf
#if (KC >= BC)
#define ROUNDS (KC + 6)
#else
#define ROUNDS (BC + 6)
#endif
#ifdef ONLY_ONE_ENCRYPTION
#define ENCRYPTION_INIT aes_ref_init
#define ENCRYPTION_CLEANUP aes_ref_cleanup
#define ENCRYPTION_DECRYPT aes_ref_decrypt
#endif
//------------------------------------------------------------------------------
// Prototypes
//------------------------------------------------------------------------------
extern void aes_ref_init(void);
extern void aes_ref_init_CBC(void);
extern void aes_ref_init_ECB(void);
extern void aes_ref_init_CTR(void);
extern void aes_ref_cleanup(void);
extern int aes_ref_decrypt(const unsigned char * cipherText,
unsigned char * plainText,
unsigned int length);
extern int aes_ref_decrypt_CBC(const unsigned char * cipherText,
unsigned char * plainText,
unsigned int length);
extern int aes_ref_decrypt_ECB(const unsigned char * cipherText,
unsigned char * plainText,
unsigned int length);
extern int aes_ref_decrypt_CTR(const unsigned char * cipherText,
unsigned char * plainText,
unsigned int length);
#endif // defined(USE_ENCRYPTION) && defined(ENCRYPTION_AES_REF)
#endif // BOOTLOADER_AES_REFERENCE_H
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