nrf_ecb.c

00001 /* Copyright (c) 2012 Nordic Semiconductor. All Rights Reserved.
00002 *
00003 * The information contained herein is property of Nordic Semiconductor ASA.
00004 * Terms and conditions of usage are described in detail in NORDIC
00005 * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT. 
00006 *
00007 * Licensees are granted free, non-transferable use of the information. NO
00008 * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
00009 * the file.
00010 *
00011 * $LastChangedRevision: 25419 $
00012 */ 
00013 
00014 /** 
00015  * @file
00016  * @brief Implementation of AES ECB driver
00017  */
00018 
00019 
00020 //lint -e438
00021 
00022 #include <stdlib.h>
00023 #include <stdbool.h>
00024 #include <string.h>
00025 #include "nrf.h" 
00026 #include "nrf_ecb.h"
00027 
00028 static uint8_t  ecb_data[48];   ///< ECB data structure for RNG peripheral to access.
00029 static uint8_t* ecb_key;        ///< Key:        Starts at ecb_data 
00030 static uint8_t* ecb_cleartext;  ///< Cleartext:  Starts at ecb_data + 16 bytes.
00031 static uint8_t* ecb_ciphertext; ///< Ciphertext: Starts at ecb_data + 32 bytes.
00032 
00033 bool nrf_ecb_init(void)
00034 {
00035   ecb_key = ecb_data;
00036   ecb_cleartext  = ecb_data + 16;
00037   ecb_ciphertext = ecb_data + 32;
00038 
00039   NRF_ECB->ECBDATAPTR = (uint32_t)ecb_data;
00040   return true;
00041 }
00042 
00043 
00044 bool nrf_ecb_crypt(uint8_t * dest_buf, const uint8_t * src_buf)
00045 {
00046    uint32_t counter = 0x1000000;
00047    if(src_buf != ecb_cleartext)
00048    {
00049      memcpy(ecb_cleartext,src_buf,16);
00050    }
00051    NRF_ECB->EVENTS_ENDECB = 0;
00052    NRF_ECB->TASKS_STARTECB = 1;
00053    while(NRF_ECB->EVENTS_ENDECB == 0)
00054    {
00055     counter--;
00056     if(counter == 0)
00057     {
00058       return false;
00059     }
00060    }
00061    NRF_ECB->EVENTS_ENDECB = 0;
00062    if(dest_buf != ecb_ciphertext)
00063    {
00064      memcpy(dest_buf,ecb_ciphertext,16);
00065    }
00066    return true;
00067 }
00068 
00069 void nrf_ecb_set_key(const uint8_t * key)
00070 {
00071   memcpy(ecb_key,key,16);
00072 }
00073 
00074