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 ) ); }
int main( int argc, char *argv[] ) { FILE *f; int i, k, ret; mbedtls_ctr_drbg_context ctr_drbg; mbedtls_entropy_context entropy; unsigned char buf[1024]; mbedtls_ctr_drbg_init( &ctr_drbg ); if( argc < 2 ) { mbedtls_fprintf( stderr, "usage: %s <output filename>\n", argv[0] ); return( 1 ); } if( ( f = fopen( argv[1], "wb+" ) ) == NULL ) { mbedtls_printf( "failed to open '%s' for writing.\n", argv[1] ); return( 1 ); } mbedtls_entropy_init( &entropy ); ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy, (const unsigned char *) "RANDOM_GEN", 10 ); if( ret != 0 ) { mbedtls_printf( "failed in mbedtls_ctr_drbg_seed: %d\n", ret ); goto cleanup; } mbedtls_ctr_drbg_set_prediction_resistance( &ctr_drbg, MBEDTLS_CTR_DRBG_PR_OFF ); #if defined(MBEDTLS_FS_IO) ret = mbedtls_ctr_drbg_update_seed_file( &ctr_drbg, "seedfile" ); if( ret == MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR ) { mbedtls_printf( "Failed to open seedfile. Generating one.\n" ); ret = mbedtls_ctr_drbg_write_seed_file( &ctr_drbg, "seedfile" ); if( ret != 0 ) { mbedtls_printf( "failed in mbedtls_ctr_drbg_write_seed_file: %d\n", ret ); goto cleanup; } } else if( ret != 0 ) { mbedtls_printf( "failed in mbedtls_ctr_drbg_update_seed_file: %d\n", ret ); goto cleanup; } #endif for( i = 0, k = 768; i < k; i++ ) { ret = mbedtls_ctr_drbg_random( &ctr_drbg, buf, sizeof( buf ) ); if( ret != 0 ) { mbedtls_printf("failed!\n"); goto cleanup; } fwrite( buf, 1, sizeof( buf ), f ); mbedtls_printf( "Generating %ldkb of data in file '%s'... %04.1f" \ "%% done\r", (long)(sizeof(buf) * k / 1024), argv[1], (100 * (float) (i + 1)) / k ); fflush( stdout ); } ret = 0; cleanup: mbedtls_printf("\n"); fclose( f ); mbedtls_ctr_drbg_free( &ctr_drbg ); mbedtls_entropy_free( &entropy ); return( ret ); }