SPIRIT_Aes.c

00001 /**
00002   ******************************************************************************
00003  * @file    SPIRIT_Aes.c
00004   * @author  VMA division - AMS
00005   * @version 3.2.2
00006   * @date    08-July-2015
00007  * @brief   Configuration and management of SPIRIT AES Engine.
00008  *
00009   * @attention
00010  *
00011   * <h2><center>&copy; COPYRIGHT(c) 2015 STMicroelectronics</center></h2>
00012  *
00013   * Redistribution and use in source and binary forms, with or without modification,
00014   * are permitted provided that the following conditions are met:
00015   *   1. Redistributions of source code must retain the above copyright notice,
00016   *      this list of conditions and the following disclaimer.
00017   *   2. Redistributions in binary form must reproduce the above copyright notice,
00018   *      this list of conditions and the following disclaimer in the documentation
00019   *      and/or other materials provided with the distribution.
00020   *   3. Neither the name of STMicroelectronics nor the names of its contributors
00021   *      may be used to endorse or promote products derived from this software
00022   *      without specific prior written permission.
00023   *
00024   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00025   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00026   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
00027   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
00028   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00029   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
00030   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00031   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
00032   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
00033   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00034   *
00035   ******************************************************************************
00036  */
00037 
00038 
00039 /* Includes ------------------------------------------------------------------*/
00040 #include "SPIRIT_Aes.h"
00041 #include "MCU_Interface.h"
00042 
00043 
00044 /**
00045  * @addtogroup SPIRIT_Libraries
00046  * @{
00047  */
00048 
00049 
00050 /**
00051  * @addtogroup SPIRIT_Aes
00052  * @{
00053  */
00054 
00055 
00056 /**
00057  * @defgroup Aes_Private_TypesDefinitions       AES Private Types Definitions
00058  * @{
00059  */
00060 
00061 /**
00062  * @}
00063  */
00064 
00065 
00066 /**
00067  * @defgroup Aes_Private_Defines                AES Private Defines
00068  * @{
00069  */
00070 
00071 /**
00072  * @}
00073  */
00074 
00075 
00076 /**
00077  * @defgroup Aes_Private_Macros                 AES Private Macros
00078  * @{
00079  */
00080 
00081 /**
00082  * @}
00083  */
00084 
00085 
00086 /**
00087  * @defgroup Aes_Private_Variables              AES Private Variables
00088  * @{
00089  */
00090 
00091 /**
00092  * @}
00093  */
00094 
00095 
00096 /**
00097  * @defgroup Aes_Private_FunctionPrototypes     AES Private Function Prototypes
00098  * @{
00099  */
00100 
00101 /**
00102  * @}
00103  */
00104 
00105 
00106 /**
00107  * @defgroup Aes_Private_Functions              AES Private Functions
00108  * @{
00109  */
00110 
00111 
00112 /**
00113  * @brief  Enables or Disables the AES engine.
00114  * @param  xNewState new state for AES engine.
00115  *         This parameter can be: S_ENABLE or S_DISABLE.
00116  * @retval None
00117  */
00118 void SpiritAesMode(SpiritFunctionalState xNewState)
00119 {
00120   uint8_t tempRegValue = 0x00;
00121 
00122   /* Check the parameters */
00123   s_assert_param(IS_SPIRIT_FUNCTIONAL_STATE(xNewState));
00124 
00125   /* Modifies the register value */
00126   g_xStatus = SpiritSpiReadRegisters(ANA_FUNC_CONF0_BASE, 1, &tempRegValue);
00127   if(xNewState == S_ENABLE)
00128   {
00129     tempRegValue |= AES_MASK;
00130   }
00131   else
00132   {
00133     tempRegValue &= ~AES_MASK;
00134   }
00135 
00136   /* Writes the ANA_FUNC_CONF0 register to enable or disable the AES engine */
00137   g_xStatus = SpiritSpiWriteRegisters(ANA_FUNC_CONF0_BASE, 1, &tempRegValue);
00138 
00139 }
00140 
00141 
00142 /**
00143  * @brief  Writes the data to encrypt or decrypt, or the encryption key for the 
00144  *         derive decryption key operation into the AES_DATA_IN registers.
00145  * @param  pcBufferDataIn pointer to the user data buffer. The first byte of the array
00146  *     shall be the MSB byte and it will be put in the AES_DATA_IN[0] register, while
00147  *     the last one shall be the LSB and it will be put in the AES_DATA_IN[cDataLength-1]
00148  *     register. If data to write are less than 16 bytes the remaining AES_DATA_IN registers
00149  *     will be filled with bytes equal to 0. This parameter is an uint8_t*.
00150  * @param  cDataLength length of data in bytes.
00151  *         This parameter is an uint8_t.
00152  * @retval None
00153  */
00154 void SpiritAesWriteDataIn(uint8_t* pcBufferDataIn, uint8_t cDataLength)
00155 {
00156   uint8_t i, dataInArray[16];
00157 
00158   /* Verifies that there are no more than 16 bytes */
00159   (cDataLength>16) ? (cDataLength=16) : cDataLength;
00160 
00161   /* Fill the dataInArray with the data buffer, using padding */
00162   for(i=0;i<16;i++)
00163   {
00164     (i<(16 - cDataLength)) ? (dataInArray[i]=0):(dataInArray[i]=pcBufferDataIn[15-i]);
00165 
00166   }
00167 
00168   /* Writes the AES_DATA_IN registers */
00169   g_xStatus = SpiritSpiWriteRegisters(AES_DATA_IN_15_BASE, 16, dataInArray);
00170 
00171 }
00172 
00173 
00174 /**
00175  * @brief  Returns the encrypted or decrypted data or the decription key from the AES_DATA_OUT register.
00176  * @param  pcBufferDataOut pointer to the user data buffer. The AES_DATA_OUT[0]
00177  *         register value will be put as first element of the buffer (MSB), while the
00178  *         AES_DAT_OUT[cDataLength-1] register value will be put as last element of the buffer (LSB).
00179  *     This parameter is a uint8_t*.
00180  * @param  cDataLength length of data to read in bytes.
00181  *         This parameter is a uint8_t.
00182  * @retval None
00183  */
00184 void SpiritAesReadDataOut(uint8_t* pcBufferDataOut, uint8_t cDataLength)
00185 {
00186   uint8_t address, dataOutArray[16];
00187 
00188   /* Verifies that there are no more than 16 bytes */
00189   (cDataLength>16) ? (cDataLength=16) : cDataLength;
00190 
00191   /* Evaluates the address of AES_DATA_OUT from which start to read */
00192   address = AES_DATA_OUT_15_BASE+16-cDataLength;
00193 
00194   /* Reads the exact number of AES_DATA_OUT registers */
00195   g_xStatus = (SpiritSpiReadRegisters(address, cDataLength, dataOutArray));
00196 
00197   /* Copy in the user buffer the read values changing the order */
00198   for(int i = (cDataLength-1); i>=0; i--)
00199   {
00200     *pcBufferDataOut = dataOutArray[i];
00201     pcBufferDataOut++;
00202   }
00203 
00204 }
00205 
00206 
00207 /**
00208  * @brief  Writes the encryption key into the AES_KEY_IN register.
00209  * @param  pcKey pointer to the buffer of 4 words containing the AES key.
00210  *         The first byte of the buffer shall be the most significant byte AES_KEY_0 of the AES key.
00211  *         The last byte of the buffer shall be the less significant byte AES_KEY_15 of the AES key.
00212  *     This parameter is an uint8_t*.
00213  * @retval None
00214  */
00215 void SpiritAesWriteKey(uint8_t* pcKey)
00216 {
00217   uint8_t pcTempKey[16]; 
00218   for (uint8_t i = 0; i < 16; i++)
00219   {
00220     pcTempKey[15-i] = pcKey[i];
00221   }
00222   
00223   /* Writes the AES_DATA_IN registers */
00224   g_xStatus = SpiritSpiWriteRegisters(AES_KEY_IN_15_BASE, 16, pcTempKey);
00225 
00226 }
00227 
00228 /**
00229  * @brief  Returns the encryption/decryption key from the AES_KEY_IN register.
00230  * @param  pcKey  pointer to the buffer of 4 words (16 bytes) containing the AES key.
00231  *         The first byte of the buffer shall be the most significant byte AES_KEY_0 of the AES key.
00232  *         The last byte of the buffer shall be the less significant byte AES_KEY_15 of the AES key.
00233  *         This parameter is an uint8_t*.
00234  * @retval None
00235  */
00236 void SpiritAesReadKey(uint8_t* pcKey)
00237 {
00238   uint8_t pcTempKey[16];
00239 
00240   /* Reads the AES_DATA_IN registers */
00241   g_xStatus = SpiritSpiReadRegisters(AES_KEY_IN_15_BASE, 16, pcTempKey);
00242 
00243 
00244   for (uint8_t i = 0; i < 16; i++)
00245     pcKey[i] = pcTempKey[15-i];
00246 
00247 }
00248 
00249 
00250 
00251 /**
00252  * @brief  Derives the decryption key from a given encryption key.
00253  * @param  None.
00254  * @retval None.
00255  */
00256 void SpiritAesDeriveDecKeyFromEnc(void)
00257 {
00258   /* Sends the COMMAND_AES_KEY command */
00259   g_xStatus = SpiritSpiCommandStrobes(COMMAND_AES_KEY);
00260 
00261 }
00262 
00263 
00264 /**
00265  * @brief  Executes the encryption operation.
00266  * @param  None.
00267  * @retval None.
00268  */
00269 void SpiritAesExecuteEncryption(void)
00270 {
00271   /* Sends the COMMAND_AES_ENC command */
00272   g_xStatus = SpiritSpiCommandStrobes(COMMAND_AES_ENC);
00273 
00274 }
00275 
00276 
00277 /**
00278  * @brief  Executes the decryption operation.
00279  * @param  None.
00280  * @retval None.
00281  */
00282 void SpiritAesExecuteDecryption(void)
00283 {
00284   /* Sends the COMMAND_AES_DEC command */
00285   g_xStatus = SpiritSpiCommandStrobes(COMMAND_AES_DEC);
00286 
00287 }
00288 
00289 
00290 /**
00291  * @brief  Executes the key derivation and the decryption operation.
00292  * @param  None.
00293  * @retval None.
00294  */
00295 void SpiritAesDeriveDecKeyExecuteDec(void)
00296 {
00297   /* Sends the COMMAND_AES_KEY_DEC command */
00298   g_xStatus = SpiritSpiCommandStrobes(COMMAND_AES_KEY_DEC);
00299 
00300 }
00301 
00302 
00303 /**
00304  * @}
00305  */
00306 
00307 
00308 /**
00309  * @}
00310  */
00311 
00312 
00313 /**
00314  * @}
00315  */
00316 
00317 
00318 
00319 /******************* (C) COPYRIGHT 2015 STMicroelectronics *****END OF FILE****/