mcuxClRandom_PRNG_Seed_example.c

Example for the mcuxClRandom component with seeding for Prng.

Example for the mcuxClRandom component with seeding for Prng

/*--------------------------------------------------------------------------*/
/* Copyright 2025 NXP                                                       */
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/* SPDX-License-Identifier: BSD-3-Clause                                    */
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#include <mcuxClCore_Examples.h>            // Defines and assertions for examples
#include <mcuxClCore_FunctionIdentifiers.h> // Code flow protection
#include <mcuxClToolchain.h>
 
#include <mcuxClBuffer.h>
#include <mcuxClExample_Session_Helper.h>
#include <mcuxClRandom.h>
#include <mcuxClSession.h>
#include <mcuxCsslFlowProtection.h>
 
#define randomDataSize (16u)
#define randomDataWordSize ((randomDataSize) / sizeof(uint32_t))

MCUXCLEXAMPLE_FUNCTION(mcuxClRandom_PRNG_Seed_example)
{
  /**************************************************************************/
  /* Preparation                                                            */
  /**************************************************************************/
 
  /**************************************************************************/
  /* In mcuxClSession_init(), the PRNG seed will be reseeded.                */
  /* A reseed is neccessary after an SGI restart/flush because the seed is  */
  /* initialized at 0x00.                                                   */
  /**************************************************************************/
  mcuxClSession_Descriptor_t sessionDesc;
  mcuxClSession_Handle_t session = &sessionDesc;
  MCUXCLEXAMPLE_ALLOCATE_AND_INITIALIZE_SESSION(session, MCUXCLRANDOM_NCINIT_WACPU_SIZE, 0u);
 
  /* Initialize PRNG. This initializes PRNG in normal / unpatched mode */
  MCUX_CSSL_ANALYSIS_START_SUPPRESS_DEREFERENCE_NULL_POINTER("session->apiCall is not NULL when accessed")
  MCUX_CSSL_FP_FUNCTION_CALL_BEGIN(nci_status, nci_token, mcuxClRandom_ncInit(session));
  MCUX_CSSL_ANALYSIS_STOP_SUPPRESS_DEREFERENCE_NULL_POINTER()
 
  if((MCUX_CSSL_FP_FUNCTION_CALLED(mcuxClRandom_ncInit) != nci_token) || (MCUXCLRANDOM_STATUS_OK != nci_status))
  {
    return MCUXCLEXAMPLE_STATUS_ERROR;
  }
  MCUX_CSSL_FP_FUNCTION_CALL_END();
 
  /**************************************************************************/
  /* Generate data for the first time                                       */
  /**************************************************************************/
 
  uint32_t pPrngData1[randomDataWordSize];
  MCUXCLBUFFER_INIT(pPrngBuffer1, session, pPrngData1, randomDataSize);
 
  /* Generate non cryptographic random values. */
  MCUX_CSSL_FP_FUNCTION_CALL_BEGIN(
    ncg_status1,
    ncg_token1,
    mcuxClRandom_ncGenerate(session, pPrngBuffer1, randomDataSize)
  );
  if((MCUX_CSSL_FP_FUNCTION_CALLED(mcuxClRandom_ncGenerate) != ncg_token1) || (MCUXCLRANDOM_STATUS_OK != ncg_status1))
  {
    return MCUXCLEXAMPLE_STATUS_ERROR;
  }
  MCUX_CSSL_FP_FUNCTION_CALL_END();
 
  /**************************************************************************/
  /* Reseed the PRNG                                                        */
  /**************************************************************************/
 
  MCUX_CSSL_FP_FUNCTION_CALL_BEGIN(ncr_status, ncr_token, mcuxClRandom_ncReseed(session));
  if((MCUX_CSSL_FP_FUNCTION_CALLED(mcuxClRandom_ncReseed) != ncr_token) || (MCUXCLRANDOM_STATUS_OK != ncr_status))
  {
    return MCUXCLEXAMPLE_STATUS_ERROR;
  }
  MCUX_CSSL_FP_FUNCTION_CALL_END();
 
  /**************************************************************************/
  /* Generate data for the second time                                      */
  /**************************************************************************/
 
  uint8_t pPrngData2[randomDataSize];
  MCUXCLBUFFER_INIT(pPrngBuffer2, session, pPrngData2, randomDataSize);
 
  /* Generate non cryptographic random values. */
  MCUX_CSSL_FP_FUNCTION_CALL_BEGIN(
    ncg_status2,
    ncg_token2,
    mcuxClRandom_ncGenerate(session, pPrngBuffer2, randomDataSize)
  );
  if((MCUX_CSSL_FP_FUNCTION_CALLED(mcuxClRandom_ncGenerate) != ncg_token2) || (MCUXCLRANDOM_STATUS_OK != ncg_status2))
  {
    return MCUXCLEXAMPLE_STATUS_ERROR;
  }
  MCUX_CSSL_FP_FUNCTION_CALL_END();
 
  /**************************************************************************/
  /* Cleanup                                                                */
  /**************************************************************************/

  if(!mcuxClExample_Session_Clean(session))
  {
    return MCUXCLEXAMPLE_STATUS_ERROR;
  }
 
  return MCUXCLEXAMPLE_STATUS_OK;
}