forked from Imagelibrary/rtems
287 lines
9.0 KiB
C
287 lines
9.0 KiB
C
/* ---------------------------------------------------------------------------- */
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/* Atmel Microcontroller Software Support */
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/* SAM Software Package License */
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/* ---------------------------------------------------------------------------- */
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/* Copyright (c) 2015, Atmel Corporation */
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/* */
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/* All rights reserved. */
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/* */
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/* Redistribution and use in source and binary forms, with or without */
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/* modification, are permitted provided that the following condition is met: */
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/* */
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/* - Redistributions of source code must retain the above copyright notice, */
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/* this list of conditions and the disclaimer below. */
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/* */
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/* Atmel's name may not be used to endorse or promote products derived from */
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/* this software without specific prior written permission. */
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/* */
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/* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR */
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/* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE */
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/* DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, */
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/* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT */
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/* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, */
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/* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF */
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/* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING */
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/* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */
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/* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
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/* ---------------------------------------------------------------------------- */
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/** \addtogroup aes_module Working with AES
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* \ingroup peripherals_module
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* The AES driver provides the interface to configure and use the AES peripheral.
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* \n
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*
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* The Advanced Encryption Standard (AES) specifies a FIPS-approved
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* cryptographic algorithm that can be used to protect electronic data. The AES
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* algorithm is a symmetric block cipher that can encrypt (encipher) and decrypt
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* (decipher) information.
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* Encryption converts data to an unintelligible form called ciphertext.
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* Decrypting the ciphertext converts the data back into its original form,
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* called plaintext. The CIPHER bit in the AES Mode Register (AES_MR) allows
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* selection between the encryption and the decryption processes. The AES is
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* capable of using cryptographic keys of 128/192/256 bits to encrypt and
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* decrypt data in blocks of 128 bits.
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* This 128-bit/192-bit/256-bit key is defined in the Key Registers (AES_KEYWRx)
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* and set by AES_WriteKey(). The input to the encryption processes of the CBC,
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* CFB, and OFB modes includes, in addition to the plaintext, a 128-bit data
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* block called the initialization vector (IV),
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* which must be set with AES_SetVector().
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* The initialization vector is used in an initial step in the encryption of a
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* message and in the corresponding decryption of the message.
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* The Initialization Vector Registers are also used by the CTR mode to set the
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* counter value.
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*
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* To Enable a AES encryption and decryption,the user has to follow these few
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* steps:
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* <ul>
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* <li> A software triggered hardware reset of the AES interface is performed
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* by AES_SoftReset().</li>
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* <li> Configure AES algorithm mode, key mode, start mode and operation mode by
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* AES_Configure(). </li>
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* <li> Input AES data for encryption and decryption with function
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* AES_SetInput() </li>
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* <li> Set AES key with function AES_WriteKey(). </li>
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* <li> To start the encryption or the decryption process with AES_Start()</li>
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* <li> To get the encryption or decryption result by AES_GetOutput() </li>
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* </ul>
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*
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*
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* For more accurate information, please look at the AES section of the
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* Datasheet.
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*
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* Related files :\n
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* \ref aes.c\n
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* \ref aes.h\n
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*/
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/*@{*/
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/*@}*/
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/**
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* \file
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*
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* Implementation of Advanced Encryption Standard (AES)
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*
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*/
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/*----------------------------------------------------------------------------
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* Headers
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*----------------------------------------------------------------------------*/
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#include "chip.h"
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#include "aes.h"
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/*----------------------------------------------------------------------------
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* Exported functions
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*----------------------------------------------------------------------------*/
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/**
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* \brief Starts Manual encryption/decryption process.
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*/
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void AES_Start(void)
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{
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AES->AES_CR = AES_CR_START;
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}
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/**
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* \brief Resets the AES. A software triggered hardware reset of the AES
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* interface is performed.
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*/
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void AES_SoftReset(void)
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{
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AES->AES_CR = AES_CR_SWRST;
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}
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/**
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* \brief Configures an AES peripheral with the specified parameters.
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* \param mode Desired value for the AES mode register (see the datasheet).
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*/
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void AES_Configure(uint32_t mode)
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{
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AES->AES_MR = mode;
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}
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/**
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* \brief Enables the selected interrupts sources on a AES peripheral.
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* \param sources Bitwise OR of selected interrupt sources.
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*/
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void AES_EnableIt(uint32_t sources)
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{
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AES->AES_IER = sources;
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}
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/**
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* \brief Disables the selected interrupts sources on a AES peripheral.
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* \param sources Bitwise OR of selected interrupt sources.
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*/
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void AES_DisableIt(uint32_t sources)
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{
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AES->AES_IDR = sources;
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}
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/**
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* \brief Get the current status register of the given AES peripheral.
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* \return AES status register.
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*/
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uint32_t AES_GetStatus(void)
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{
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return AES->AES_ISR;
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}
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/**
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* \brief Set the 128-bit/192-bit/256-bit cryptographic key used for
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* encryption/decryption.
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* \param pKey Pointer to a 16/24/32 bytes cipher key.
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* \param keyLength length of key
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*/
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void AES_WriteKey(const uint32_t *pKey, uint32_t keyLength)
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{
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AES->AES_KEYWR[0] = pKey[0];
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AES->AES_KEYWR[1] = pKey[1];
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AES->AES_KEYWR[2] = pKey[2];
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AES->AES_KEYWR[3] = pKey[3];
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if (keyLength >= 24) {
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AES->AES_KEYWR[4] = pKey[4];
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AES->AES_KEYWR[5] = pKey[5];
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}
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if (keyLength == 32) {
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AES->AES_KEYWR[6] = pKey[6];
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AES->AES_KEYWR[7] = pKey[7];
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}
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}
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/**
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* \brief Set the for 32-bit input Data allow to set the 128-bit data block
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* used for encryption/decryption.
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* \param data Pointer to the 16-bytes data to cipher/decipher.
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*/
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void AES_SetInput(const uint32_t *data)
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{
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uint8_t i;
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for (i = 0; i < 4; i++)
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AES->AES_IDATAR[i] = data[i];
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}
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/**
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* \brief Get the four 32-bit data contain the 128-bit data block which
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* has been encrypted/decrypted.
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* \param data pointer to the word that has been encrypted/decrypted..
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*/
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void AES_GetOutput(uint32_t *data)
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{
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uint8_t i;
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for (i = 0; i < 4; i++)
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data[i] = AES->AES_ODATAR[i];
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}
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/**
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* \brief Set four 64-bit initialization vector data block, which is used by
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* some modes of operation as an additional initial input.
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* \param pVector point to the word of the initialization vector.
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*/
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void AES_SetVector(const uint32_t *pVector)
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{
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AES->AES_IVR[0] = pVector[0];
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AES->AES_IVR[1] = pVector[1];
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AES->AES_IVR[2] = pVector[2];
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AES->AES_IVR[3] = pVector[3];
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}
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/**
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* \brief Set Length in bytes of the AAD data that is to be processed.
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* \param len Length.
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*/
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void AES_SetAadLen(uint32_t len)
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{
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AES->AES_AADLENR = len;
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}
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/**
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* \brief Set Length in bytes of the Length in bytes of the
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* plaintext/ciphertext (C) data that is to be processed..
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* \param len Length.
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*/
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void AES_SetDataLen(uint32_t len)
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{
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AES->AES_CLENR = len;
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}
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/**
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* \brief Set The four 32-bit Hash Word registers expose the intermediate GHASH
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* value. May be read to save the current GHASH value so processing can later be
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* resumed, presumably on a later message fragment. modes of operation as an
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* additional initial input.
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* \param hash point to the word of the hash.
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*/
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void AES_SetGcmHash(uint32_t *hash)
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{
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uint8_t i;
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for (i = 0; i < 4; i++)
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AES->AES_GHASHR[i] = hash[i];
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}
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/**
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* \brief Get The four 32-bit Tag which contain the final 128-bit GCM
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* Authentication tag <20><>T<EFBFBD><54> when GCM processing is complete.
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* \param tag point to the word of the tag.
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*/
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void AES_GetGcmTag(uint32_t *tag)
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{
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uint8_t i;
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for (i = 0; i < 4; i++)
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tag[i] = AES->AES_TAGR[i];
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}
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/**
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* \brief Reports the current value of the 32-bit GCM counter
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* \param counter Point to value of GCM counter.
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*/
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void AES_GetGcmCounter(uint32_t *counter)
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{
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*counter = AES->AES_CTRR;
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}
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/**
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* \brief Get the four 32-bit data contain the 128-bit H value computed from
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* the KEYW value
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* \param data point to the word that has been encrypted/decrypted.
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*/
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void AES_GetGcmH(uint32_t *h)
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{
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uint8_t i;
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for (i = 0; i < 4; i++)
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h[i] = AES->AES_GCMHR[i];
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}
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