File content as of revision 167:356ef919c855:

/**
 * @file    aes.h
 * @brief   Advanced Encryption Standard (AES) function prototypes and data types.
 */

/* ****************************************************************************
 * Copyright (C) 2016 Maxim Integrated Products, Inc., All Rights Reserved.
 *
 * 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 MAXIM INTEGRATED 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.
 *
 * Except as contained in this notice, the name of Maxim Integrated
 * Products, Inc. shall not be used except as stated in the Maxim Integrated
 * Products, Inc. Branding Policy.
 *
 * The mere transfer of this software does not imply any licenses
 * of trade secrets, proprietary technology, copyrights, patents,
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 *
 * $Date: 2016-08-02 13:39:05 -0500 (Tue, 02 Aug 2016) $
 * $Revision: 23894 $
 *
  *************************************************************************** */

/* Define to prevent redundant inclusion */
#ifndef _AES_H
#define _AES_H

#include <stdint.h>
#include "aes_regs.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @defgroup aes Advanced Encryption Standard (AES)
 * @ingroup periphlibs
 * @brief High-level API for AES encryption engine
 * @{
 */

/**
 * @page aes_overview Overview and Usage
 * @parblock
 * #### Key/data format in memory
 *
 * The API functions require that key and plain/ciphertext will be stored as a
 * byte array in LSB .. MSB format.
 *
 * As an example, given the key @a 0x139a35422f1d61de3c91787fe0507afd, the proper storage order is:
 * ~~~~~
 * uint8_t key[16] = { 0xfd, 0x7a, 0x50, 0xe0,
 *                     0x7f, 0x78, 0x91, 0x3c,
 *                     0xde, 0x61, 0x1d, 0x2f,
 *                     0x42, 0x35, 0x9a, 0x13 };
 * ~~~~~
 * This is the same order expected by the underlying hardware.
 * @endparblock
 */

/* **** Definitions **** */

#define MXC_AES_DATA_LEN (128 / 8)          /**< Number of bytes in an AES plaintext or cyphertext block (always 128-bits) */

#define MXC_AES_KEY_128_LEN (128 / 8)       /**< Number of bytes in a AES-128 key */
#define MXC_AES_KEY_192_LEN (192 / 8)       /**< Number of bytes in a AES-192 key */
#define MXC_AES_KEY_256_LEN (256 / 8)       /**< Number of bytes in a AES-256 key */

/**
 * Enumeration type for AES key size selection (bits).
 */
typedef enum {
    MXC_E_AES_MODE_128 = MXC_V_AES_CTRL_KEY_SIZE_128,       /**< 128-bit key */
    MXC_E_AES_MODE_192 = MXC_V_AES_CTRL_KEY_SIZE_192,       /**< 192-bit key */
    MXC_E_AES_MODE_256 = MXC_V_AES_CTRL_KEY_SIZE_256        /**< 256-bit key */
} mxc_aes_mode_t;

/**
 * Enumeration type for specifying encryption/decrytion and asynchronous or blocking behavior.
 */
typedef enum {
    MXC_E_AES_ENCRYPT = 0,                                  /**< Encrypt (blocking) */
    MXC_E_AES_ENCRYPT_ASYNC = 1,                            /**< Encrypt (interrupt-driven) */
    MXC_E_AES_DECRYPT = 2,                                  /**< Decrypt (blocking) */
    MXC_E_AES_DECRYPT_ASYNC = 3                             /**< Decrypt (interrupt-driven) */
} mxc_aes_dir_t;

/* **** Function Prototypes **** */

/**
 * @brief Configure AES block with keying material
 *
 * @param       key             128, 192, or 256 bit keying material
 * @param       mode            Selects key length, valid modes defined in #mxc_aes_mode_t
 *
 * @return      #E_BAD_PARAM    Specified @a mode is invalid, see #mxc_aes_mode_t.
 * @return      #E_NULL_PTR     Invalid/Null pointer for parameter @a key.
 * @return      #E_SUCCESS      Key and mode set up correctly.
 */
int AES_SetKey(const uint8_t *key, mxc_aes_mode_t mode);


/**
 * @brief       Encrypt/decrypt an input block with the loaded AES key.
 * @note        The parameters @a in and @a out should always be 16 bytes
 *
 * @param       in              Pointer to input array of 16 bytes.
 * @param       out             Pointer to output array of 16 bytes.
 * @param       mode            AES key size to use for the transaction, see #mxc_aes_mode_t
 * @param       dir             Encrypt/Decrypt and Blocking or Asynchronous operation, see #mxc_aes_dir_t.
 *
 * @return      #E_SUCCESS      Operation completed successfully, output data is stored in @a *out.
 * @return      ErrorCode       An @link MXC_Error_Codes Error Code@endlink.
 */
int AES_ECBOp(const uint8_t *in, uint8_t *out, mxc_aes_mode_t mode, mxc_aes_dir_t dir);

/**
 * @brief       Read the AES output memory, used for asynchronous encryption, and clears interrupt flag.
 * @note        The parameter @a out is always 16 bytes
 *
 * @param       out             Pointer to output array of 16 bytes
 *
 * @return      #E_SUCCESS      Output data was written to the location pointed to by @a *out
 * @return      Error Code indicating the type of error encountered. See @ref MXC_Error_Codes
 *              for possible return code values.
 */
int AES_GetOutput(uint8_t *out);

/**
 * @def AES_ECBEncrypt(ptxt, ctxt, mode)s
 * @brief Encrypt a block of plaintext with the loaded AES key, blocks until complete
 * @hideinitializer
 *
 * @param ptxt                Pointer to plaintext input array (always 16 bytes)
 * @param ctxt                Pointer to ciphertext output array (always 16 bytes)
 * @param mode                Selects key length, valid modes found in mxc_aes_mode_t
 */
#define AES_ECBEncrypt(ptxt, ctxt, mode) AES_ECBOp(ptxt, ctxt, mode, MXC_E_AES_ENCRYPT)


/**
 * @def AES_ECBDecrypt(ctxt, ptxt, mode)
 * @hideinitializer
 * @brief Decrypt a block of ciphertext with the loaded AES key, blocks until complete
 *
 * @param ctxt                Pointer to ciphertext output array (always 16 bytes)
 * @param ptxt                Pointer to plaintext input array (always 16 bytes)
 * @param mode                Selects key length, valid modes found in mxc_aes_mode_t
 */
#define AES_ECBDecrypt(ctxt, ptxt, mode) AES_ECBOp(ctxt, ptxt, mode, MXC_E_AES_DECRYPT)

/**
 * @def AES_ECBEncryptAsync(ptxt, mode)
 * @hideinitializer
 * @brief Starts encryption of a block, enables interrupt, and returns immediately.
 *        Use AES_GetOuput() to retrieve result after interrupt fires
 *
 *
 * @param ptxt                Pointer to plaintext input array (always 16 bytes)
 * @param mode                Selects key length, valid modes found in mxc_aes_mode_t
 */
#define AES_ECBEncryptAsync(ptxt, mode) AES_ECBOp(ptxt, NULL, mode, MXC_E_AES_ENCRYPT_ASYNC)

/**
 * @def AES_ECBDecryptAsync(ctxt, mode)
 * @hideinitializer
 * @brief Starts encryption of a block, enables interrupt, and returns immediately.
 *        Use AES_GetOuput() to retrieve result after interrupt fires
 *
 * @param ctxt                Pointer to ciphertext output array (always 16 bytes)
 * @param mode                Selects key length, valid modes found in mxc_aes_mode_t
 */
#define AES_ECBDecryptAsync(ctxt, mode) AES_ECBOp(ctxt, NULL, mode, MXC_E_AES_DECRYPT_ASYNC)

/**@} end of group aes*/

#ifdef __cplusplus
}
#endif

#endif