/* ---------------------------------------------------------------------------- | |
* SAM Software Package License | |
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* Copyright (c) 2013, Atmel Corporation | |
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/** \addtogroup aes_module Working with AES | |
* \ingroup peripherals_module | |
* The AES driver provides the interface to configure and use the AES peripheral. | |
* \n | |
* | |
* The Advanced Encryption Standard (AES) specifies a FIPS-approved cryptographic algorithm | |
* that can be used to protect electronic data. The AES algorithm is a symmetric block | |
* cipher that can encrypt (encipher) and decrypt (decipher) information. | |
* Encryption converts data to an unintelligible form called ciphertext. | |
* Decrypting the ciphertext converts the data back into its original form, | |
* called plaintext. The CIPHER bit in the AES Mode Register (AES_MR) allows selection | |
* between the encryption and the decryption processes. The AES is capable of using cryptographic | |
* keys of 128/192/256 bits to encrypt and decrypt data in blocks of 128 bits. | |
* This 128-bit/192-bit/256-bit key is defined in the Key Registers (AES_KEYWRx) and set by | |
* AES_WriteKey(). The input to the encryption processes of the CBC, CFB, and OFB modes includes, | |
* in addition to the plaintext, a 128-bit data block called the initialization vector (IV), | |
* which must be set with AES_SetVector(). | |
* The initialization vector is used in an initial step in the encryption of a message and | |
* in the corresponding decryption of the message. The Initialization Vector Registers are | |
* also used by the CTR mode to set the counter value. | |
* | |
* To Enable a AES encryption and decryption,the user has to follow these few steps: | |
* <ul> | |
* <li> A software triggered hardware reset of the AES interface is performed by AES_SoftReset().</li> | |
* <li> Configure AES algorithm mode, key mode, start mode and operation mode by AES_Configure(). </li> | |
* <li> Input AES data for encryption and decryption with function AES_SetInput() </li> | |
* <li> Set AES key with function AES_WriteKey(). </li> | |
* <li> To start the encryption or the decryption process with AES_Start()</li> | |
* <li> To get the encryption or decryption result by AES_GetOutput() </li> | |
* </ul> | |
* | |
* | |
* For more accurate information, please look at the AES section of the | |
* Datasheet. | |
* | |
* Related files :\n | |
* \ref aes.c\n | |
* \ref aes.h\n | |
*/ | |
/*@{*/ | |
/*@}*/ | |
/** | |
* \file | |
* | |
* Implementation of Advanced Encryption Standard (AES) | |
* | |
*/ | |
/*---------------------------------------------------------------------------- | |
* Headers | |
*----------------------------------------------------------------------------*/ | |
#include "chip.h" | |
/*---------------------------------------------------------------------------- | |
* Exported functions | |
*----------------------------------------------------------------------------*/ | |
/** | |
* \brief Starts Manual encryption/decryption process. | |
*/ | |
void AES_Start(void) | |
{ | |
AES->AES_CR = AES_CR_START; | |
} | |
/** | |
* \brief Resets the AES. A software triggered hardware reset of the AES interface is performed. | |
*/ | |
void AES_SoftReset(void) | |
{ | |
AES->AES_CR = AES_CR_SWRST; | |
} | |
/** | |
* \brief Configures an AES peripheral with the specified parameters. | |
* \param mode Desired value for the AES mode register (see the datasheet). | |
*/ | |
void AES_Configure(uint32_t mode) | |
{ | |
AES->AES_MR = mode; | |
} | |
/** | |
* \brief Enables the selected interrupts sources on a AES peripheral. | |
* \param sources Bitwise OR of selected interrupt sources. | |
*/ | |
void AES_EnableIt(uint32_t sources) | |
{ | |
AES->AES_IER = sources; | |
} | |
/** | |
* \brief Disables the selected interrupts sources on a AES peripheral. | |
* \param sources Bitwise OR of selected interrupt sources. | |
*/ | |
void AES_DisableIt(uint32_t sources) | |
{ | |
AES->AES_IDR = sources; | |
} | |
/** | |
* \brief Get the current status register of the given AES peripheral. | |
* \return AES status register. | |
*/ | |
uint32_t AES_GetStatus(void) | |
{ | |
return AES->AES_ISR; | |
} | |
/** | |
* \brief Set the 128-bit/192-bit/256-bit cryptographic key used for encryption/decryption. | |
* \param pKey Pointer to a 16/24/32 bytes cipher key. | |
* \param keyLength length of key | |
*/ | |
void AES_WriteKey(const uint32_t *pKey, uint32_t keyLength) | |
{ | |
AES->AES_KEYWR[0] = pKey[0]; | |
AES->AES_KEYWR[1] = pKey[1]; | |
AES->AES_KEYWR[2] = pKey[2]; | |
AES->AES_KEYWR[3] = pKey[3]; | |
if( keyLength >= 24 ) { | |
AES->AES_KEYWR[4] = pKey[4]; | |
AES->AES_KEYWR[5] = pKey[5]; | |
} | |
if( keyLength == 32 ) { | |
AES->AES_KEYWR[6] = pKey[6]; | |
AES->AES_KEYWR[7] = pKey[7]; | |
} | |
} | |
/** | |
* \brief Set the for 32-bit input Data allow to set the 128-bit data block used for encryption/decryption. | |
* \param data Pointer to the 16-bytes data to cipher/decipher. | |
*/ | |
void AES_SetInput(uint32_t *data) | |
{ | |
uint8_t i; | |
for (i = 0; i< 4; i++) | |
AES->AES_IDATAR[i] = data[i]; | |
} | |
/** | |
* \brief Get the four 32-bit data contain the 128-bit data block which has been encrypted/decrypted. | |
* \param data pointer to the word that has been encrypted/decrypted.. | |
*/ | |
void AES_GetOutput(uint32_t *data) | |
{ | |
uint8_t i; | |
for (i = 0; i< 4; i++) | |
data[i] = AES->AES_ODATAR[i]; | |
} | |
/** | |
* \brief Set four 64-bit initialization vector data block, which is used by some | |
* modes of operation as an additional initial input. | |
* \param pVector point to the word of the initialization vector. | |
*/ | |
void AES_SetVector(const uint32_t *pVector) | |
{ | |
AES->AES_IVR[0] = pVector[0]; | |
AES->AES_IVR[1] = pVector[1]; | |
AES->AES_IVR[2] = pVector[2]; | |
AES->AES_IVR[3] = pVector[3]; | |
} | |
/** | |
* \brief Set Length in bytes of the AAD data that is to be processed. | |
* \param len Length. | |
*/ | |
void AES_SetAadLen(uint32_t len) | |
{ | |
AES->AES_AADLENR = len; | |
} | |
/** | |
* \brief Set Length in bytes of the Length in bytes of the | |
* plaintext/ciphertext (C) data that is to be processed.. | |
* \param len Length. | |
*/ | |
void AES_SetDataLen(uint32_t len) | |
{ | |
AES->AES_CLENR = len; | |
} | |
/** | |
* \brief Set The four 32-bit Hash Word registers expose the intermediate GHASH value. | |
* May be read to save the current GHASH value so processing can later be resumed, | |
* presumably on a later message fragment. modes of operation as an additional initial input. | |
* \param hash point to the word of the hash. | |
*/ | |
void AES_SetGcmHash(uint32_t * hash) | |
{ | |
uint8_t i; | |
for (i = 0; i< 4; i++) | |
AES->AES_GHASHR[i] = hash[i]; | |
} | |
/** | |
* \brief Get The four 32-bit Tag which contain the final 128-bit GCM Authentication tag | |
* ¡°T¡± when GCM processing is complete. | |
* \param tag point to the word of the tag. | |
*/ | |
void AES_GetGcmTag(uint32_t * tag) | |
{ | |
uint8_t i; | |
for (i = 0; i< 4; i++) | |
tag[i] = AES->AES_TAGR[i] ; | |
} | |
/** | |
* \brief Reports the current value of the 32-bit GCM counter | |
* \param counter Point to value of GCM counter. | |
*/ | |
void AES_GetGcmCounter(uint32_t * counter) | |
{ | |
*counter = AES->AES_CTRR; | |
} | |
/** | |
* \brief Get the four 32-bit data contain the 128-bit H value computed from the KEYW value | |
* \param data point to the word that has been encrypted/decrypted.. | |
*/ | |
void AES_GetGcmH(uint32_t *h) | |
{ | |
uint8_t i; | |
for (i = 0; i< 4; i++) | |
h[i] = AES->AES_GCMHR[i]; | |
} | |