tests/suites/test_suite_ecdh.function - security/mbedtls - Rivoreo Source Code Repositories

 /* BEGIN_HEADER */
 #include "mbedtls/ecdh.h"
 /* END_HEADER */

 /* BEGIN_DEPENDENCIES
  * depends_on:MBEDTLS_ECDH_C
  * END_DEPENDENCIES
  */

 /* BEGIN_CASE */
 void ecdh_primitive_random( int id )
 {
     mbedtls_ecp_group grp;
     mbedtls_ecp_point qA, qB;
     mbedtls_mpi dA, dB, zA, zB;
     rnd_pseudo_info rnd_info;

     mbedtls_ecp_group_init( &grp );
     mbedtls_ecp_point_init( &qA ); mbedtls_ecp_point_init( &qB );
     mbedtls_mpi_init( &dA ); mbedtls_mpi_init( &dB );
     mbedtls_mpi_init( &zA ); mbedtls_mpi_init( &zB );
     memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );

     TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );

     TEST_ASSERT( mbedtls_ecdh_gen_public( &grp, &dA, &qA, &rnd_pseudo_rand, &rnd_info )
                  == 0 );
     TEST_ASSERT( mbedtls_ecdh_gen_public( &grp, &dB, &qB, &rnd_pseudo_rand, &rnd_info )
                  == 0 );
     TEST_ASSERT( mbedtls_ecdh_compute_shared( &grp, &zA, &qB, &dA,
                                       &rnd_pseudo_rand, &rnd_info ) == 0 );
     TEST_ASSERT( mbedtls_ecdh_compute_shared( &grp, &zB, &qA, &dB,
                                       NULL, NULL ) == 0 );

     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &zA, &zB ) == 0 );

 exit:
     mbedtls_ecp_group_free( &grp );
     mbedtls_ecp_point_free( &qA ); mbedtls_ecp_point_free( &qB );
     mbedtls_mpi_free( &dA ); mbedtls_mpi_free( &dB );
     mbedtls_mpi_free( &zA ); mbedtls_mpi_free( &zB );
 }
 /* END_CASE */

 /* BEGIN_CASE */
 void ecdh_primitive_testvec( int id, data_t * rnd_buf_A, char * xA_str,
                              char * yA_str, data_t * rnd_buf_B,
                              char * xB_str, char * yB_str, char * z_str )
 {
     mbedtls_ecp_group grp;
     mbedtls_ecp_point qA, qB;
     mbedtls_mpi dA, dB, zA, zB, check;
     rnd_buf_info rnd_info_A, rnd_info_B;

     mbedtls_ecp_group_init( &grp );
     mbedtls_ecp_point_init( &qA ); mbedtls_ecp_point_init( &qB );
     mbedtls_mpi_init( &dA ); mbedtls_mpi_init( &dB );
     mbedtls_mpi_init( &zA ); mbedtls_mpi_init( &zB ); mbedtls_mpi_init( &check );

     TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );

     rnd_info_A.buf = rnd_buf_A->x;
     rnd_info_A.length = rnd_buf_A->len;

     /* Fix rnd_buf_A->x by shifting it left if necessary */
     if( grp.nbits % 8 != 0 )
     {
         unsigned char shift = 8 - ( grp.nbits % 8 );
         size_t i;

         for( i = 0; i < rnd_info_A.length - 1; i++ )
             rnd_buf_A->x[i] = rnd_buf_A->x[i] << shift
                          | rnd_buf_A->x[i+1] >> ( 8 - shift );

         rnd_buf_A->x[rnd_info_A.length-1] <<= shift;
     }

     rnd_info_B.buf = rnd_buf_B->x;
     rnd_info_B.length = rnd_buf_B->len;

     /* Fix rnd_buf_B->x by shifting it left if necessary */
     if( grp.nbits % 8 != 0 )
     {
         unsigned char shift = 8 - ( grp.nbits % 8 );
         size_t i;

         for( i = 0; i < rnd_info_B.length - 1; i++ )
             rnd_buf_B->x[i] = rnd_buf_B->x[i] << shift
                          | rnd_buf_B->x[i+1] >> ( 8 - shift );

         rnd_buf_B->x[rnd_info_B.length-1] <<= shift;
     }

     TEST_ASSERT( mbedtls_ecdh_gen_public( &grp, &dA, &qA,
                                   rnd_buffer_rand, &rnd_info_A ) == 0 );
     TEST_ASSERT( ! mbedtls_ecp_is_zero( &qA ) );
     TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, xA_str ) == 0 );
     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &qA.X, &check ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, yA_str ) == 0 );
     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &qA.Y, &check ) == 0 );

     TEST_ASSERT( mbedtls_ecdh_gen_public( &grp, &dB, &qB,
                                   rnd_buffer_rand, &rnd_info_B ) == 0 );
     TEST_ASSERT( ! mbedtls_ecp_is_zero( &qB ) );
     TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, xB_str ) == 0 );
     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &qB.X, &check ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, yB_str ) == 0 );
     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &qB.Y, &check ) == 0 );

     TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, z_str ) == 0 );
     TEST_ASSERT( mbedtls_ecdh_compute_shared( &grp, &zA, &qB, &dA, NULL, NULL ) == 0 );
     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &zA, &check ) == 0 );
     TEST_ASSERT( mbedtls_ecdh_compute_shared( &grp, &zB, &qA, &dB, NULL, NULL ) == 0 );
     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &zB, &check ) == 0 );

 exit:
     mbedtls_ecp_group_free( &grp );
     mbedtls_ecp_point_free( &qA ); mbedtls_ecp_point_free( &qB );
     mbedtls_mpi_free( &dA ); mbedtls_mpi_free( &dB );
     mbedtls_mpi_free( &zA ); mbedtls_mpi_free( &zB ); mbedtls_mpi_free( &check );
 }
 /* END_CASE */

 /* BEGIN_CASE */
 void ecdh_exchange( int id )
 {
     mbedtls_ecdh_context srv, cli;
     unsigned char buf[1000];
     const unsigned char *vbuf;
     size_t len;
     rnd_pseudo_info rnd_info;

     mbedtls_ecdh_init( &srv );
     mbedtls_ecdh_init( &cli );
     memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );

     TEST_ASSERT( mbedtls_ecp_group_load( &srv.grp, id ) == 0 );

     memset( buf, 0x00, sizeof( buf ) ); vbuf = buf;
     TEST_ASSERT( mbedtls_ecdh_make_params( &srv, &len, buf, 1000,
                                    &rnd_pseudo_rand, &rnd_info ) == 0 );
     TEST_ASSERT( mbedtls_ecdh_read_params( &cli, &vbuf, buf + len ) == 0 );

     memset( buf, 0x00, sizeof( buf ) );
     TEST_ASSERT( mbedtls_ecdh_make_public( &cli, &len, buf, 1000,
                                    &rnd_pseudo_rand, &rnd_info ) == 0 );
     TEST_ASSERT( mbedtls_ecdh_read_public( &srv, buf, len ) == 0 );

     TEST_ASSERT( mbedtls_ecdh_calc_secret( &srv, &len, buf, 1000,
                                    &rnd_pseudo_rand, &rnd_info ) == 0 );
     TEST_ASSERT( mbedtls_ecdh_calc_secret( &cli, &len, buf, 1000, NULL, NULL ) == 0 );
     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &srv.z, &cli.z ) == 0 );

 exit:
     mbedtls_ecdh_free( &srv );
     mbedtls_ecdh_free( &cli );
 }
 /* END_CASE */

 /* BEGIN_CASE depends_on:MBEDTLS_ECP_RESTARTABLE */
 void ecdh_restart( int id, char *dA_str, char *dB_str, char *z_str,
                    int enable, int max_ops, int min_restart, int max_restart )
 {
     int ret;
     mbedtls_ecdh_context srv, cli;
     unsigned char buf[1000];
     const unsigned char *vbuf;
     size_t len;
     unsigned char z[MBEDTLS_ECP_MAX_BYTES];
     size_t z_len;
     unsigned char rnd_buf_A[MBEDTLS_ECP_MAX_BYTES];
     unsigned char rnd_buf_B[MBEDTLS_ECP_MAX_BYTES];
     rnd_buf_info rnd_info_A, rnd_info_B;
     int cnt_restart;

     mbedtls_ecdh_init( &srv );
     mbedtls_ecdh_init( &cli );

     z_len = unhexify( z, z_str );

     rnd_info_A.buf = rnd_buf_A;
     rnd_info_A.length = unhexify( rnd_buf_A, dA_str );

     rnd_info_B.buf = rnd_buf_B;
     rnd_info_B.length = unhexify( rnd_buf_B, dB_str );

     TEST_ASSERT( mbedtls_ecp_group_load( &srv.grp, id ) == 0 );

     /* otherwise we would have to fix the random buffer,
      * as in ecdh_primitive_test_vec */
     TEST_ASSERT( srv.grp.nbits % 8 == 0 );

     /* set up restart parameters */
     mbedtls_ecp_set_max_ops( max_ops );

     if( enable)
     {
         mbedtls_ecdh_enable_restart( &srv );
         mbedtls_ecdh_enable_restart( &cli );
     }

     /* server writes its paramaters */
     memset( buf, 0x00, sizeof( buf ) );
     len = 0;

     cnt_restart = 0;
     do {
         ret = mbedtls_ecdh_make_params( &srv, &len, buf, sizeof( buf ),
                                         rnd_buffer_rand, &rnd_info_A );
     } while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

     TEST_ASSERT( ret == 0 );
     TEST_ASSERT( cnt_restart >= min_restart );
     TEST_ASSERT( cnt_restart <= max_restart );

     /* client read server params */
     vbuf = buf;
     TEST_ASSERT( mbedtls_ecdh_read_params( &cli, &vbuf, buf + len ) == 0 );

     /* client writes its key share */
     memset( buf, 0x00, sizeof( buf ) );
     len = 0;

     cnt_restart = 0;
     do {
         ret = mbedtls_ecdh_make_public( &cli, &len, buf, sizeof( buf ),
                                         rnd_buffer_rand, &rnd_info_B );
     } while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

     TEST_ASSERT( ret == 0 );
     TEST_ASSERT( cnt_restart >= min_restart );
     TEST_ASSERT( cnt_restart <= max_restart );

     /* server reads client key share */
     TEST_ASSERT( mbedtls_ecdh_read_public( &srv, buf, len ) == 0 );

     /* server computes shared secret */
     memset( buf, 0, sizeof( buf ) );
     len = 0;

     cnt_restart = 0;
     do {
         ret = mbedtls_ecdh_calc_secret( &srv, &len, buf, sizeof( buf ),
                                               NULL, NULL );
     } while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

     TEST_ASSERT( ret == 0 );
     TEST_ASSERT( cnt_restart >= min_restart );
     TEST_ASSERT( cnt_restart <= max_restart );

     TEST_ASSERT( len == z_len );
     TEST_ASSERT( memcmp( buf, z, len ) == 0 );

     /* client computes shared secret */
     memset( buf, 0, sizeof( buf ) );
     len = 0;

     cnt_restart = 0;
     do {
         ret = mbedtls_ecdh_calc_secret( &cli, &len, buf, sizeof( buf ),
                                               NULL, NULL );
     } while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

     TEST_ASSERT( ret == 0 );
     TEST_ASSERT( cnt_restart >= min_restart );
     TEST_ASSERT( cnt_restart <= max_restart );

     TEST_ASSERT( len == z_len );
     TEST_ASSERT( memcmp( buf, z, len ) == 0 );

 exit:
     mbedtls_ecdh_free( &srv );
     mbedtls_ecdh_free( &cli );
 }
 /* END_CASE */
	/* BEGIN_HEADER */
	#include "mbedtls/ecdh.h"
	/* END_HEADER */

	/* BEGIN_DEPENDENCIES
	* depends_on:MBEDTLS_ECDH_C
	* END_DEPENDENCIES
	*/

	/* BEGIN_CASE */
	void ecdh_primitive_random( int id )
	{
	mbedtls_ecp_group grp;
	mbedtls_ecp_point qA, qB;
	mbedtls_mpi dA, dB, zA, zB;
	rnd_pseudo_info rnd_info;

	mbedtls_ecp_group_init( &grp );
	mbedtls_ecp_point_init( &qA ); mbedtls_ecp_point_init( &qB );
	mbedtls_mpi_init( &dA ); mbedtls_mpi_init( &dB );
	mbedtls_mpi_init( &zA ); mbedtls_mpi_init( &zB );
	memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );

	TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );

	TEST_ASSERT( mbedtls_ecdh_gen_public( &grp, &dA, &qA, &rnd_pseudo_rand, &rnd_info )
	== 0 );
	TEST_ASSERT( mbedtls_ecdh_gen_public( &grp, &dB, &qB, &rnd_pseudo_rand, &rnd_info )
	== 0 );
	TEST_ASSERT( mbedtls_ecdh_compute_shared( &grp, &zA, &qB, &dA,
	&rnd_pseudo_rand, &rnd_info ) == 0 );
	TEST_ASSERT( mbedtls_ecdh_compute_shared( &grp, &zB, &qA, &dB,
	NULL, NULL ) == 0 );

	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &zA, &zB ) == 0 );

	exit:
	mbedtls_ecp_group_free( &grp );
	mbedtls_ecp_point_free( &qA ); mbedtls_ecp_point_free( &qB );
	mbedtls_mpi_free( &dA ); mbedtls_mpi_free( &dB );
	mbedtls_mpi_free( &zA ); mbedtls_mpi_free( &zB );
	}
	/* END_CASE */

	/* BEGIN_CASE */
	void ecdh_primitive_testvec( int id, data_t * rnd_buf_A, char * xA_str,
	char * yA_str, data_t * rnd_buf_B,
	char * xB_str, char * yB_str, char * z_str )
	{
	mbedtls_ecp_group grp;
	mbedtls_ecp_point qA, qB;
	mbedtls_mpi dA, dB, zA, zB, check;
	rnd_buf_info rnd_info_A, rnd_info_B;

	mbedtls_ecp_group_init( &grp );
	mbedtls_ecp_point_init( &qA ); mbedtls_ecp_point_init( &qB );
	mbedtls_mpi_init( &dA ); mbedtls_mpi_init( &dB );
	mbedtls_mpi_init( &zA ); mbedtls_mpi_init( &zB ); mbedtls_mpi_init( &check );

	TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );

	rnd_info_A.buf = rnd_buf_A->x;
	rnd_info_A.length = rnd_buf_A->len;

	/* Fix rnd_buf_A->x by shifting it left if necessary */
	if( grp.nbits % 8 != 0 )
	{
	unsigned char shift = 8 - ( grp.nbits % 8 );
	size_t i;

	for( i = 0; i < rnd_info_A.length - 1; i++ )
	rnd_buf_A->x[i] = rnd_buf_A->x[i] << shift
	\| rnd_buf_A->x[i+1] >> ( 8 - shift );

	rnd_buf_A->x[rnd_info_A.length-1] <<= shift;
	}

	rnd_info_B.buf = rnd_buf_B->x;
	rnd_info_B.length = rnd_buf_B->len;

	/* Fix rnd_buf_B->x by shifting it left if necessary */
	if( grp.nbits % 8 != 0 )
	{
	unsigned char shift = 8 - ( grp.nbits % 8 );
	size_t i;

	for( i = 0; i < rnd_info_B.length - 1; i++ )
	rnd_buf_B->x[i] = rnd_buf_B->x[i] << shift
	\| rnd_buf_B->x[i+1] >> ( 8 - shift );

	rnd_buf_B->x[rnd_info_B.length-1] <<= shift;
	}

	TEST_ASSERT( mbedtls_ecdh_gen_public( &grp, &dA, &qA,
	rnd_buffer_rand, &rnd_info_A ) == 0 );
	TEST_ASSERT( ! mbedtls_ecp_is_zero( &qA ) );
	TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, xA_str ) == 0 );
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &qA.X, &check ) == 0 );
	TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, yA_str ) == 0 );
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &qA.Y, &check ) == 0 );

	TEST_ASSERT( mbedtls_ecdh_gen_public( &grp, &dB, &qB,
	rnd_buffer_rand, &rnd_info_B ) == 0 );
	TEST_ASSERT( ! mbedtls_ecp_is_zero( &qB ) );
	TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, xB_str ) == 0 );
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &qB.X, &check ) == 0 );
	TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, yB_str ) == 0 );
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &qB.Y, &check ) == 0 );

	TEST_ASSERT( mbedtls_mpi_read_string( &check, 16, z_str ) == 0 );
	TEST_ASSERT( mbedtls_ecdh_compute_shared( &grp, &zA, &qB, &dA, NULL, NULL ) == 0 );
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &zA, &check ) == 0 );
	TEST_ASSERT( mbedtls_ecdh_compute_shared( &grp, &zB, &qA, &dB, NULL, NULL ) == 0 );
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &zB, &check ) == 0 );

	exit:
	mbedtls_ecp_group_free( &grp );
	mbedtls_ecp_point_free( &qA ); mbedtls_ecp_point_free( &qB );
	mbedtls_mpi_free( &dA ); mbedtls_mpi_free( &dB );
	mbedtls_mpi_free( &zA ); mbedtls_mpi_free( &zB ); mbedtls_mpi_free( &check );
	}
	/* END_CASE */

	/* BEGIN_CASE */
	void ecdh_exchange( int id )
	{
	mbedtls_ecdh_context srv, cli;
	unsigned char buf[1000];
	const unsigned char *vbuf;
	size_t len;
	rnd_pseudo_info rnd_info;

	mbedtls_ecdh_init( &srv );
	mbedtls_ecdh_init( &cli );
	memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );

	TEST_ASSERT( mbedtls_ecp_group_load( &srv.grp, id ) == 0 );

	memset( buf, 0x00, sizeof( buf ) ); vbuf = buf;
	TEST_ASSERT( mbedtls_ecdh_make_params( &srv, &len, buf, 1000,
	&rnd_pseudo_rand, &rnd_info ) == 0 );
	TEST_ASSERT( mbedtls_ecdh_read_params( &cli, &vbuf, buf + len ) == 0 );

	memset( buf, 0x00, sizeof( buf ) );
	TEST_ASSERT( mbedtls_ecdh_make_public( &cli, &len, buf, 1000,
	&rnd_pseudo_rand, &rnd_info ) == 0 );
	TEST_ASSERT( mbedtls_ecdh_read_public( &srv, buf, len ) == 0 );

	TEST_ASSERT( mbedtls_ecdh_calc_secret( &srv, &len, buf, 1000,
	&rnd_pseudo_rand, &rnd_info ) == 0 );
	TEST_ASSERT( mbedtls_ecdh_calc_secret( &cli, &len, buf, 1000, NULL, NULL ) == 0 );
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &srv.z, &cli.z ) == 0 );

	exit:
	mbedtls_ecdh_free( &srv );
	mbedtls_ecdh_free( &cli );
	}
	/* END_CASE */

	/* BEGIN_CASE depends_on:MBEDTLS_ECP_RESTARTABLE */
	void ecdh_restart( int id, char dA_str, char dB_str, char *z_str,
	int enable, int max_ops, int min_restart, int max_restart )
	{
	int ret;
	mbedtls_ecdh_context srv, cli;
	unsigned char buf[1000];
	const unsigned char *vbuf;
	size_t len;
	unsigned char z[MBEDTLS_ECP_MAX_BYTES];
	size_t z_len;
	unsigned char rnd_buf_A[MBEDTLS_ECP_MAX_BYTES];
	unsigned char rnd_buf_B[MBEDTLS_ECP_MAX_BYTES];
	rnd_buf_info rnd_info_A, rnd_info_B;
	int cnt_restart;

	mbedtls_ecdh_init( &srv );
	mbedtls_ecdh_init( &cli );

	z_len = unhexify( z, z_str );

	rnd_info_A.buf = rnd_buf_A;
	rnd_info_A.length = unhexify( rnd_buf_A, dA_str );

	rnd_info_B.buf = rnd_buf_B;
	rnd_info_B.length = unhexify( rnd_buf_B, dB_str );

	TEST_ASSERT( mbedtls_ecp_group_load( &srv.grp, id ) == 0 );

	/* otherwise we would have to fix the random buffer,
	* as in ecdh_primitive_test_vec */
	TEST_ASSERT( srv.grp.nbits % 8 == 0 );

	/* set up restart parameters */
	mbedtls_ecp_set_max_ops( max_ops );

	if( enable)
	{
	mbedtls_ecdh_enable_restart( &srv );
	mbedtls_ecdh_enable_restart( &cli );
	}

	/* server writes its paramaters */
	memset( buf, 0x00, sizeof( buf ) );
	len = 0;

	cnt_restart = 0;
	do {
	ret = mbedtls_ecdh_make_params( &srv, &len, buf, sizeof( buf ),
	rnd_buffer_rand, &rnd_info_A );
	} while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

	TEST_ASSERT( ret == 0 );
	TEST_ASSERT( cnt_restart >= min_restart );
	TEST_ASSERT( cnt_restart <= max_restart );

	/* client read server params */
	vbuf = buf;
	TEST_ASSERT( mbedtls_ecdh_read_params( &cli, &vbuf, buf + len ) == 0 );

	/* client writes its key share */
	memset( buf, 0x00, sizeof( buf ) );
	len = 0;

	cnt_restart = 0;
	do {
	ret = mbedtls_ecdh_make_public( &cli, &len, buf, sizeof( buf ),
	rnd_buffer_rand, &rnd_info_B );
	} while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

	TEST_ASSERT( ret == 0 );
	TEST_ASSERT( cnt_restart >= min_restart );
	TEST_ASSERT( cnt_restart <= max_restart );

	/* server reads client key share */
	TEST_ASSERT( mbedtls_ecdh_read_public( &srv, buf, len ) == 0 );

	/* server computes shared secret */
	memset( buf, 0, sizeof( buf ) );
	len = 0;

	cnt_restart = 0;
	do {
	ret = mbedtls_ecdh_calc_secret( &srv, &len, buf, sizeof( buf ),
	NULL, NULL );
	} while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

	TEST_ASSERT( ret == 0 );
	TEST_ASSERT( cnt_restart >= min_restart );
	TEST_ASSERT( cnt_restart <= max_restart );

	TEST_ASSERT( len == z_len );
	TEST_ASSERT( memcmp( buf, z, len ) == 0 );

	/* client computes shared secret */
	memset( buf, 0, sizeof( buf ) );
	len = 0;

	cnt_restart = 0;
	do {
	ret = mbedtls_ecdh_calc_secret( &cli, &len, buf, sizeof( buf ),
	NULL, NULL );
	} while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

	TEST_ASSERT( ret == 0 );
	TEST_ASSERT( cnt_restart >= min_restart );
	TEST_ASSERT( cnt_restart <= max_restart );

	TEST_ASSERT( len == z_len );
	TEST_ASSERT( memcmp( buf, z, len ) == 0 );

	exit:
	mbedtls_ecdh_free( &srv );
	mbedtls_ecdh_free( &cli );
	}
	/* END_CASE */