text: /*
   *  CTR_DRBG implementation based on AES-256 (NIST SP 800-90)
   *
   *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   *  SPDX-License-Identifier: Apache-2.0
   *
   *  Licensed under the Apache License, Version 2.0 (the "License"); you may
   *  not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *  http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *  This file is part of mbed TLS (https://tls.mbed.org)
   */
  /*
   *  The NIST SP 800-90 DRBGs are described in the following publucation.
   *
   *  http://csrc.nist.gov/publications/nistpubs/800-90/SP800-90revised_March2007.pdf
   */
  
  #if !defined(MBEDTLS_CONFIG_FILE)
  #include "mbedtls/config.h"
  #else
  #include MBEDTLS_CONFIG_FILE
  #endif
  
  #if defined(MBEDTLS_CTR_DRBG_C)
  
  #ifndef MBEDTLS_DRBG_ALT
  
  #include "mbedtls/ctr_drbg.h"
  
  #include <string.h>
  
  #if defined(MBEDTLS_FS_IO)
  #include <stdio.h>
  #endif
  
  #if defined(MBEDTLS_SELF_TEST)
  #if defined(MBEDTLS_PLATFORM_C)
  #include "mbedtls/platform.h"
  #else
  #include <stdio.h>
  #define mbedtls_printf printf
  #endif /* MBEDTLS_PLATFORM_C */
  #endif /* MBEDTLS_SELF_TEST */
  
  /* Implementation that should never be optimized out by the compiler */
  static void mbedtls_zeroize( void *v, size_t n ) {
      volatile unsigned char *p = v; while( n-- ) *p++ = 0;
  }
  
  /*
   * CTR_DRBG context initialization
   */
  void mbedtls_ctr_drbg_init( mbedtls_ctr_drbg_context *ctx )
  {
      memset( ctx, 0, sizeof( mbedtls_ctr_drbg_context ) );
  
  #if defined(MBEDTLS_THREADING_C)
      mbedtls_mutex_init( &ctx->mutex );
  #endif
  }
  
  /*
   * Non-public function wrapped by mbedtls_ctr_drbg_seed(). Necessary to allow
   * NIST tests to succeed (which require known length fixed entropy)
   */
  int mbedtls_ctr_drbg_seed_entropy_len(
                     mbedtls_ctr_drbg_context *ctx,
                     int (*f_entropy)(void *, unsigned char *, size_t),
                     void *p_entropy,
                     const unsigned char *custom,
                     size_t len,
                     size_t entropy_len )
  {
      int ret;
      unsigned char key[MBEDTLS_CTR_DRBG_KEYSIZE];
  
      memset( key, 0, MBEDTLS_CTR_DRBG_KEYSIZE );
  
      mbedtls_aes_init( &ctx->aes_ctx );
  
      ctx->f_entropy = f_entropy;
      ctx->p_entropy = p_entropy;
  
      ctx->entropy_len = entropy_len;
      ctx->reseed_interval = MBEDTLS_CTR_DRBG_RESEED_INTERVAL;
  
      /*
       * Initialize with an empty key
       */
      mbedtls_aes_setkey_enc( &ctx->aes_ctx, key, MBEDTLS_CTR_DRBG_KEYBITS );
  
      if( ( ret = mbedtls_ctr_drbg_reseed( ctx, custom, len ) ) != 0 )
          return( ret );
  
      return( 0 );
  }
  
  int mbedtls_ctr_drbg_seed( mbedtls_ctr_drbg_context *ctx,
                     int (*f_entropy)(void *, unsigned char *, size_t),
                     void *p_entropy,
                     const unsigned char *custom,
                     size_t len )
  {
      return( mbedtls_ctr_drbg_seed_entropy_len( ctx, f_entropy, p_entropy, custom, len,
                                         MBEDTLS_CTR_DRBG_ENTROPY_LEN ) );
  }
  
  void mbedtls_ctr_drbg_free( mbedtls_ctr_drbg_context *ctx )
  {
      if( ctx == NULL )
          return;
  
  #if defined(MBEDTLS_THREADING_C)
      mbedtls_mutex_free( &ctx->mutex );
  #endif
      mbedtls_aes_free( &ctx->aes_ctx );
      mbedtls_zeroize( ctx, sizeof( mbedtls_ctr_drbg_context ) );
  }
  
  void mbedtls_ctr_drbg_set_prediction_resistance( mbedtls_ctr_drbg_context *ctx, int resistance )
  {
      ctx->prediction_resistance = resistance;
  }
  
  void mbedtls_ctr_drbg_set_entropy_len( mbedtls_ctr_drbg_context *ctx, size_t len )
  {
      ctx->entropy_len = len;
  }
  
  void mbedtls_ctr_drbg_set_reseed_interval( mbedtls_ctr_drbg_context *ctx, int interval )
  {
      ctx->reseed_interval = interval;
  }
  
  static int block_cipher_df( unsigned char *output,
                              const unsigned char *data, size_t data_len )
  {
      unsigned char buf[MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + MBEDTLS_CTR_DRBG_BLOCKSIZE + 16];
      unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN];
      unsigned char key[MBEDTLS_CTR_DRBG_KEYSIZE];
      unsigned char chain[MBEDTLS_CTR_DRBG_BLOCKSIZE];
      unsigned char *p, *iv;
      mbedtls_aes_context aes_ctx;
  
      int i, j;
      size_t buf_len, use_len;
  
      if( data_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT )
          return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
  
      memset( buf, 0, MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + MBEDTLS_CTR_DRBG_BLOCKSIZE + 16 );
      mbedtls_aes_init( &aes_ctx );
  
      /*
       * Construct IV (16 bytes) and S in buffer
       * IV = Counter (in 32-bits) padded to 16 with zeroes
       * S = Length input string (in 32-bits) || Length of output (in 32-bits) ||
       *     data || 0x80
       *     (Total is padded to a multiple of 16-bytes with zeroes)
       */
      p = buf + MBEDTLS_CTR_DRBG_BLOCKSIZE;
      *p++ = ( data_len >> 24 ) & 0xff;
      *p++ = ( data_len >> 16 ) & 0xff;
      *p++ = ( data_len >> 8  ) & 0xff;
      *p++ = ( data_len       ) & 0xff;
      p += 3;
      *p++ = MBEDTLS_CTR_DRBG_SEEDLEN;
      memcpy( p, data, data_len );
      p[data_len] = 0x80;
  
      buf_len = MBEDTLS_CTR_DRBG_BLOCKSIZE + 8 + data_len + 1;
  
      for( i = 0; i < MBEDTLS_CTR_DRBG_KEYSIZE; i++ )
          key[i] = i;
  
      mbedtls_aes_setkey_enc( &aes_ctx, key, MBEDTLS_CTR_DRBG_KEYBITS );
  
      /*
       * Reduce data to MBEDTLS_CTR_DRBG_SEEDLEN bytes of data
       */
      for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE )
      {
          p = buf;
          memset( chain, 0, MBEDTLS_CTR_DRBG_BLOCKSIZE );
          use_len = buf_len;
  
          while( use_len > 0 )
          {
              for( i = 0; i < MBEDTLS_CTR_DRBG_BLOCKSIZE; i++ )
                  chain[i] ^= p[i];
              p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
              use_len -= ( use_len >= MBEDTLS_CTR_DRBG_BLOCKSIZE ) ?
                         MBEDTLS_CTR_DRBG_BLOCKSIZE : use_len;
  
              mbedtls_aes_crypt_ecb( &aes_ctx, MBEDTLS_AES_ENCRYPT, chain, chain );
          }
  
          memcpy( tmp + j, chain, MBEDTLS_CTR_DRBG_BLOCKSIZE );
  
          /*
           * Update IV
           */
          buf[3]++;
      }
  
      /*
       * Do final encryption with reduced data
       */
      mbedtls_aes_setkey_enc( &aes_ctx, tmp, MBEDTLS_CTR_DRBG_KEYBITS );
      iv = tmp + MBEDTLS_CTR_DRBG_KEYSIZE;
      p = output;
  
      for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE )
      {
          mbedtls_aes_crypt_ecb( &aes_ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
          memcpy( p, iv, MBEDTLS_CTR_DRBG_BLOCKSIZE );
          p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
      }
  
      mbedtls_aes_free( &aes_ctx );
  
      return( 0 );
  }
  
  static int ctr_drbg_update_internal( mbedtls_ctr_drbg_context *ctx,
                                const unsigned char data[MBEDTLS_CTR_DRBG_SEEDLEN] )
  {
      unsigned char tmp[MBEDTLS_CTR_DRBG_SEEDLEN];
      unsigned char *p = tmp;
      int i, j;
  
      memset( tmp, 0, MBEDTLS_CTR_DRBG_SEEDLEN );
  
      for( j = 0; j < MBEDTLS_CTR_DRBG_SEEDLEN; j += MBEDTLS_CTR_DRBG_BLOCKSIZE )
      {
          /*
           * Increase counter
           */
          for( i = MBEDTLS_CTR_DRBG_BLOCKSIZE; i > 0; i-- )
              if( ++ctx->counter[i - 1] != 0 )
                  break;
  
          /*
           * Crypt counter block
           */
          mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT, ctx->counter, p );
  
          p += MBEDTLS_CTR_DRBG_BLOCKSIZE;
      }
  
      for( i = 0; i < MBEDTLS_CTR_DRBG_SEEDLEN; i++ )
          tmp[i] ^= data[i];
  
      /*
       * Update key and counter
       */
      mbedtls_aes_setkey_enc( &ctx->aes_ctx, tmp, MBEDTLS_CTR_DRBG_KEYBITS );
      memcpy( ctx->counter, tmp + MBEDTLS_CTR_DRBG_KEYSIZE, MBEDTLS_CTR_DRBG_BLOCKSIZE );
  
      return( 0 );
  }
  
  void mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx,
                        const unsigned char *additional, size_t add_len )
  {
      unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN];
  
      if( add_len > 0 )
      {
          /* MAX_INPUT would be more logical here, but we have to match
           * block_cipher_df()'s limits since we can't propagate errors */
          if( add_len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT )
              add_len = MBEDTLS_CTR_DRBG_MAX_SEED_INPUT;
  
          block_cipher_df( add_input, additional, add_len );
          ctr_drbg_update_internal( ctx, add_input );
      }
  }
  
  int mbedtls_ctr_drbg_reseed( mbedtls_ctr_drbg_context *ctx,
                       const unsigned char *additional, size_t len )
  {
      unsigned char seed[MBEDTLS_CTR_DRBG_MAX_SEED_INPUT];
      size_t seedlen = 0;
  
      if( ctx->entropy_len + len > MBEDTLS_CTR_DRBG_MAX_SEED_INPUT )
          return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
  
      memset( seed, 0, MBEDTLS_CTR_DRBG_MAX_SEED_INPUT );
  
      /*
       * Gather entropy_len bytes of entropy to seed state
       */
      if( 0 != ctx->f_entropy( ctx->p_entropy, seed,
                               ctx->entropy_len ) )
      {
          return( MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED );
      }
  
      seedlen += ctx->entropy_len;
  
      /*
       * Add additional data
       */
      if( additional && len )
      {
          memcpy( seed + seedlen, additional, len );
          seedlen += len;
      }
  
      /*
       * Reduce to 384 bits
       */
      block_cipher_df( seed, seed, seedlen );
  
      /*
       * Update state
       */
      ctr_drbg_update_internal( ctx, seed );
      ctx->reseed_counter = 1;
  
      return( 0 );
  }
  
  int mbedtls_ctr_drbg_random_with_add( void *p_rng,
                                unsigned char *output, size_t output_len,
                                const unsigned char *additional, size_t add_len )
  {
      int ret = 0;
      mbedtls_ctr_drbg_context *ctx = (mbedtls_ctr_drbg_context *) p_rng;
      unsigned char add_input[MBEDTLS_CTR_DRBG_SEEDLEN];
      unsigned char *p = output;
      unsigned char tmp[MBEDTLS_CTR_DRBG_BLOCKSIZE];
      int i;
      size_t use_len;
  
      if( output_len > MBEDTLS_CTR_DRBG_MAX_REQUEST )
          return( MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG );
  
      if( add_len > MBEDTLS_CTR_DRBG_MAX_INPUT )
          return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
  
      memset( add_input, 0, MBEDTLS_CTR_DRBG_SEEDLEN );
  
      if( ctx->reseed_counter > ctx->reseed_interval ||
          ctx->prediction_resistance )
      {
          if( ( ret = mbedtls_ctr_drbg_reseed( ctx, additional, add_len ) ) != 0 )
              return( ret );
  
          add_len = 0;
      }
  
      if( add_len > 0 )
      {
          block_cipher_df( add_input, additional, add_len );
          ctr_drbg_update_internal( ctx, add_input );
      }
  
      while( output_len > 0 )
      {
          /*
           * Increase counter
           */
          for( i = MBEDTLS_CTR_DRBG_BLOCKSIZE; i > 0; i-- )
              if( ++ctx->counter[i - 1] != 0 )
                  break;
  
          /*
           * Crypt counter block
           */
          mbedtls_aes_crypt_ecb( &ctx->aes_ctx, MBEDTLS_AES_ENCRYPT, ctx->counter, tmp );
  
          use_len = ( output_len > MBEDTLS_CTR_DRBG_BLOCKSIZE ) ? MBEDTLS_CTR_DRBG_BLOCKSIZE :
                                                         output_len;
          /*
           * Copy random block to destination
           */
          memcpy( p, tmp, use_len );
          p += use_len;
          output_len -= use_len;
      }
  
      ctr_drbg_update_internal( ctx, add_input );
  
      ctx->reseed_counter++;
  
      return( 0 );
  }
  
  int mbedtls_ctr_drbg_random( void *p_rng, unsigned char *output, size_t output_len )
  {
      int ret;
      mbedtls_ctr_drbg_context *ctx = (mbedtls_ctr_drbg_context *) p_rng;
  
  #if defined(MBEDTLS_THREADING_C)
      if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 )
          return( ret );
  #endif
  
      ret = mbedtls_ctr_drbg_random_with_add( ctx, output, output_len, NULL, 0 );
  
  #if defined(MBEDTLS_THREADING_C)
      if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 )
          return( MBEDTLS_ERR_THREADING_MUTEX_ERROR );
  #endif
  
      return( ret );
  }
  
  #if defined(MBEDTLS_FS_IO)
  int mbedtls_ctr_drbg_write_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path )
  {
      int ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR;
      FILE *f;
      unsigned char buf[ MBEDTLS_CTR_DRBG_MAX_INPUT ];
  
      if( ( f = fopen( path, "wb" ) ) == NULL )
          return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR );
  
      if( ( ret = mbedtls_ctr_drbg_random( ctx, buf, MBEDTLS_CTR_DRBG_MAX_INPUT ) ) != 0 )
          goto exit;
  
      if( fwrite( buf, 1, MBEDTLS_CTR_DRBG_MAX_INPUT, f ) != MBEDTLS_CTR_DRBG_MAX_INPUT )
      {
          ret = MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR;
          goto exit;
      }
  
      ret = 0;
  
  exit:
      fclose( f );
      return( ret );
  }
  
  int mbedtls_ctr_drbg_update_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path )
  {
      FILE *f;
      size_t n;
      unsigned char buf[ MBEDTLS_CTR_DRBG_MAX_INPUT ];
  
      if( ( f = fopen( path, "rb" ) ) == NULL )
          return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR );
  
      fseek( f, 0, SEEK_END );
      n = (size_t) ftell( f );
      fseek( f, 0, SEEK_SET );
  
      if( n > MBEDTLS_CTR_DRBG_MAX_INPUT )
      {
          fclose( f );
          return( MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
      }
  
      if( fread( buf, 1, n, f ) != n )
      {
          fclose( f );
          return( MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR );
      }
  
      fclose( f );
  
      mbedtls_ctr_drbg_update( ctx, buf, n );
  
      return( mbedtls_ctr_drbg_write_seed_file( ctx, path ) );
  }
  #endif /* MBEDTLS_FS_IO */
  
  #if defined(MBEDTLS_SELF_TEST)
  
  static const unsigned char entropy_source_pr[96] =
      { 0xc1, 0x80, 0x81, 0xa6, 0x5d, 0x44, 0x02, 0x16,
        0x19, 0xb3, 0xf1, 0x80, 0xb1, 0xc9, 0x20, 0x02,
        0x6a, 0x54, 0x6f, 0x0c, 0x70, 0x81, 0x49, 0x8b,
        0x6e, 0xa6, 0x62, 0x52, 0x6d, 0x51, 0xb1, 0xcb,
        0x58, 0x3b, 0xfa, 0xd5, 0x37, 0x5f, 0xfb, 0xc9,
        0xff, 0x46, 0xd2, 0x19, 0xc7, 0x22, 0x3e, 0x95,
        0x45, 0x9d, 0x82, 0xe1, 0xe7, 0x22, 0x9f, 0x63,
        0x31, 0x69, 0xd2, 0x6b, 0x57, 0x47, 0x4f, 0xa3,
        0x37, 0xc9, 0x98, 0x1c, 0x0b, 0xfb, 0x91, 0x31,
        0x4d, 0x55, 0xb9, 0xe9, 0x1c, 0x5a, 0x5e, 0xe4,
        0x93, 0x92, 0xcf, 0xc5, 0x23, 0x12, 0xd5, 0x56,
        0x2c, 0x4a, 0x6e, 0xff, 0xdc, 0x10, 0xd0, 0x68 };
  
  static const unsigned char entropy_source_nopr[64] =
      { 0x5a, 0x19, 0x4d, 0x5e, 0x2b, 0x31, 0x58, 0x14,
        0x54, 0xde, 0xf6, 0x75, 0xfb, 0x79, 0x58, 0xfe,
        0xc7, 0xdb, 0x87, 0x3e, 0x56, 0x89, 0xfc, 0x9d,
        0x03, 0x21, 0x7c, 0x68, 0xd8, 0x03, 0x38, 0x20,
        0xf9, 0xe6, 0x5e, 0x04, 0xd8, 0x56, 0xf3, 0xa9,
        0xc4, 0x4a, 0x4c, 0xbd, 0xc1, 0xd0, 0x08, 0x46,
        0xf5, 0x98, 0x3d, 0x77, 0x1c, 0x1b, 0x13, 0x7e,
        0x4e, 0x0f, 0x9d, 0x8e, 0xf4, 0x09, 0xf9, 0x2e };
  
  static const unsigned char nonce_pers_pr[16] =
      { 0xd2, 0x54, 0xfc, 0xff, 0x02, 0x1e, 0x69, 0xd2,
        0x29, 0xc9, 0xcf, 0xad, 0x85, 0xfa, 0x48, 0x6c };
  
  static const unsigned char nonce_pers_nopr[16] =
      { 0x1b, 0x54, 0xb8, 0xff, 0x06, 0x42, 0xbf, 0xf5,
        0x21, 0xf1, 0x5c, 0x1c, 0x0b, 0x66, 0x5f, 0x3f };
  
  static const unsigned char result_pr[16] =
      { 0x34, 0x01, 0x16, 0x56, 0xb4, 0x29, 0x00, 0x8f,
        0x35, 0x63, 0xec, 0xb5, 0xf2, 0x59, 0x07, 0x23 };
  
  static const unsigned char result_nopr[16] =
      { 0xa0, 0x54, 0x30, 0x3d, 0x8a, 0x7e, 0xa9, 0x88,
        0x9d, 0x90, 0x3e, 0x07, 0x7c, 0x6f, 0x21, 0x8f };
  
  static size_t test_offset;
  static int ctr_drbg_self_test_entropy( void *data, unsigned char *buf,
                                         size_t len )
  {
      const unsigned char *p = data;
      memcpy( buf, p + test_offset, len );
      test_offset += len;
      return( 0 );
  }
  
  #define CHK( c )    if( (c) != 0 )                          \
                      {                                       \
                          if( verbose != 0 )                  \
                              mbedtls_printf( "failed\n" );  \
                          return( 1 );                        \
                      }
  
  /*
   * Checkup routine
   */
  int mbedtls_ctr_drbg_self_test( int verbose )
  {
      mbedtls_ctr_drbg_context ctx;
      unsigned char buf[16];
  
      mbedtls_ctr_drbg_init( &ctx );
  
      /*
       * Based on a NIST CTR_DRBG test vector (PR = True)
       */
      if( verbose != 0 )
          mbedtls_printf( "  CTR_DRBG (PR = TRUE) : " );
  
      test_offset = 0;
      CHK( mbedtls_ctr_drbg_seed_entropy_len( &ctx, ctr_drbg_self_test_entropy,
                                  (void *) entropy_source_pr, nonce_pers_pr, 16, 32 ) );
      mbedtls_ctr_drbg_set_prediction_resistance( &ctx, MBEDTLS_CTR_DRBG_PR_ON );
      CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
      CHK( mbedtls_ctr_drbg_random( &ctx, buf, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
      CHK( memcmp( buf, result_pr, MBEDTLS_CTR_DRBG_BLOCKSIZE ) );
  
      mbedtls_ctr_drbg_free( &ctx );
  
      if( verbose != 0 )
          mbedtls_printf( "passed\n" );
  
      /*
       * Based on a NIST CTR_DRBG test vector (PR = FALSE)
       */
      if( verbose != 0 )
          mbedtls_printf( "  CTR_DRBG (PR = FALSE): " );
  
      mbedtls_ctr_drbg_init( &ctx );
  
      test_offset = 0;
      CHK( mbedtls_ctr_drbg_seed_entropy_len( &ctx, ctr_drbg_self_test_entropy,
                              (void *) entropy_source_nopr, nonce_pers_nopr, 16, 32 ) );
      CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) );
      CHK( mbedtls_ctr_drbg_reseed( &ctx, NULL, 0 ) );
      CHK( mbedtls_ctr_drbg_random( &ctx, buf, 16 ) );
      CHK( memcmp( buf, result_nopr, 16 ) );
  
      mbedtls_ctr_drbg_free( &ctx );
  
      if( verbose != 0 )
          mbedtls_printf( "passed\n" );
  
      if( verbose != 0 )
              mbedtls_printf( "\n" );
  
      return( 0 );
  }
  #endif /* MBEDTLS_SELF_TEST */
  
  #else /* MBEDTLS_DRBG_ALT */
  
  #include "rda_trng_api.h"
  int mbedtls_ctr_drbg_random( void *p_rng, unsigned char *output, unsigned int output_len )
  {
      rda_trng_generator(output, output_len);
      return( 0 );
  }
  #endif /* MBEDTLS_DRBG_ALT */
  
  #endif /* MBEDTLS_CTR_DRBG_C */
  