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Use of STM32L4 HAL_CRYP hardware in LORAWAN

JVida.18
Associate II

I've tried to find an example code of use of crypto harware accelerator in LORAWAN but i haven't been able to find any . Does someone have an example expecially concerning the use of AES CMAC?

Regards

3 REPLIES 3

If you have a chip with the CYPT unit the examples for the EVAL, and other, boards can be ported into other applications and use cases.

STM32Cube_FW_L4_V1.14.0\Projects\STM32L476G-EVAL\Examples\CRYP\CRYP_GCM_GMAC_CMAC_Modes

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JVida.18
Associate II

Thank you, the example is nice for CMAC implementation, regards!

JVida.18
Associate II

still strugglign with LORAWAN CMAC... i've made this code, but i'm making a mistake...

// original code modified

void LoRaMacComputeMic( const uint8_t *buffer, uint16_t size, const uint8_t *key, uint32_t address, uint8_t dir, uint32_t sequenceCounter, uint32_t *mic )

{

  MicBlockB0[5] = dir;

  MicBlockB0[6] = ( address ) & 0xFF;

  MicBlockB0[7] = ( address >> 8 ) & 0xFF;

  MicBlockB0[8] = ( address >> 16 ) & 0xFF;

  MicBlockB0[9] = ( address >> 24 ) & 0xFF;

  MicBlockB0[10] = ( sequenceCounter ) & 0xFF;

  MicBlockB0[11] = ( sequenceCounter >> 8 ) & 0xFF;

  MicBlockB0[12] = ( sequenceCounter >> 16 ) & 0xFF;

  MicBlockB0[13] = ( sequenceCounter >> 24 ) & 0xFF;

  MicBlockB0[15] = size & 0xFF;

#ifdef USE_HAL_CRYP_MODULE

AES128_CMAC_digest(buffer, size,MicBlockB0, key, Mic);

#else

  AES_CMAC_Init( AesCmacCtx );

  AES_CMAC_SetKey( AesCmacCtx, key );

  AES_CMAC_Update( AesCmacCtx, MicBlockB0, LORAMAC_MIC_BLOCK_B0_SIZE )

  AES_CMAC_Update( AesCmacCtx, buffer, size & 0xFF )

  AES_CMAC_Final( Mic, AesCmacCtx );

#endif

  *mic = ( uint32_t )( ( uint32_t )Mic[3] << 24 | ( uint32_t )Mic[2] << 16 | ( uint32_t )Mic[1] << 8 | ( uint32_t )Mic[0] );

}

//************* then the function using hardware CMAC looks like *****************************

void __attribute__((section(".OSmsk"))) AES128_CMAC_digest(uint8_t* input, uint16_t size, uint8_t* MicBlockB0, const uint8_t* key, uint8_t* output){

hcrypt.Init.DataType   = CRYP_DATATYPE_8B ;

hcrypt.Init.KeySize    = CRYP_KEYSIZE_128B ;

hcrypt.Init.pKey     = key;

hcrypt.Init.OperatingMode = CRYP_ALGOMODE_TAG_GENERATION;

hcrypt.Init.ChainingMode = CRYP_CHAINMODE_AES_CMAC;

hcrypt.Init.GCMCMACPhase = CRYP_GCMCMAC_HEADER_PHASE;

hcrypt.Init.KeyWriteFlag = CRYP_KEY_WRITE_ENABLE;

hcrypt.Init.Header    = (uint8_t *)input;

  hcrypt.Init.HeaderSize  = CMAC_HEADER_SIZE;

   /****************************************************************************/

   /* De-initialize then initialize the AES peripheral             */

  /****************************************************************************/

  if (HAL_CRYP_DeInit(&hcrypt) != HAL_OK)

  {

      breakpoint();

  }

  /* Set the CRYP parameters */

  if (HAL_CRYP_Init(&hcrypt) != HAL_OK)

  {

     breakpoint();

  }

  /*----------------------------------------------------------------------------------------------*/

  /* CMAC header phase */

  if (MicBlockB0!=NULL){

   if (HAL_CRYPEx_AES_Auth(&hcrypt, (uint8_t *)MicBlockB0, CMAC_B_SIZE, NULL, 100)!= HAL_OK)

   {

   breakpoint();

   }

  }

  /*----------------------------------------------------------------------------------------------*/

  /* CMAC final phase */

  hcrypt.Init.GCMCMACPhase = CRYP_GCMCMAC_FINAL_PHASE;

  if (HAL_CRYPEx_AES_Auth(&hcrypt, (uint8_t *)input, size, NULL, 100)!= HAL_OK)

  {

   breakpoint();

  }

}

Does anyone made LORAWAN CMAC working using STM32 hardware HAL_CRYP?

Regards