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

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

 /* BEGIN_DEPENDENCIES
  * depends_on:MBEDTLS_ECDSA_C
  * END_DEPENDENCIES
  */

 /* BEGIN_CASE */
 void ecdsa_prim_random( int id )
 {
     mbedtls_ecp_group grp;
     mbedtls_ecp_point Q;
     mbedtls_mpi d, r, s;
     rnd_pseudo_info rnd_info;
     unsigned char buf[MBEDTLS_MD_MAX_SIZE];

     mbedtls_ecp_group_init( &grp );
     mbedtls_ecp_point_init( &Q );
     mbedtls_mpi_init( &d ); mbedtls_mpi_init( &r ); mbedtls_mpi_init( &s );
     memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );
     memset( buf, 0, sizeof( buf ) );

     /* prepare material for signature */
     TEST_ASSERT( rnd_pseudo_rand( &rnd_info, buf, sizeof( buf ) ) == 0 );
     TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
     TEST_ASSERT( mbedtls_ecp_gen_keypair( &grp, &d, &Q, &rnd_pseudo_rand, &rnd_info )
                  == 0 );

     TEST_ASSERT( mbedtls_ecdsa_sign( &grp, &r, &s, &d, buf, sizeof( buf ),
                              &rnd_pseudo_rand, &rnd_info ) == 0 );
     TEST_ASSERT( mbedtls_ecdsa_verify( &grp, buf, sizeof( buf ), &Q, &r, &s ) == 0 );

 exit:
     mbedtls_ecp_group_free( &grp );
     mbedtls_ecp_point_free( &Q );
     mbedtls_mpi_free( &d ); mbedtls_mpi_free( &r ); mbedtls_mpi_free( &s );
 }
 /* END_CASE */

 /* BEGIN_CASE */
 void ecdsa_prim_test_vectors( int id, char * d_str, char * xQ_str,
                               char * yQ_str, data_t * rnd_buf,
                               data_t * hash, char * r_str, char * s_str,
                               int result )
 {
     mbedtls_ecp_group grp;
     mbedtls_ecp_point Q;
     mbedtls_mpi d, r, s, r_check, s_check;
     rnd_buf_info rnd_info;

     mbedtls_ecp_group_init( &grp );
     mbedtls_ecp_point_init( &Q );
     mbedtls_mpi_init( &d ); mbedtls_mpi_init( &r ); mbedtls_mpi_init( &s );
     mbedtls_mpi_init( &r_check ); mbedtls_mpi_init( &s_check );

     TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
     TEST_ASSERT( mbedtls_ecp_point_read_string( &Q, 16, xQ_str, yQ_str ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &d, 16, d_str ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &r_check, 16, r_str ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &s_check, 16, s_str ) == 0 );
     rnd_info.buf = rnd_buf->x;
     rnd_info.length = rnd_buf->len;

     /* Fix rnd_buf->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.length - 1; i++ )
             rnd_buf->x[i] = rnd_buf->x[i] << shift | rnd_buf->x[i+1] >> ( 8 - shift );

         rnd_buf->x[rnd_info.length-1] <<= shift;
     }

     TEST_ASSERT( mbedtls_ecdsa_sign( &grp, &r, &s, &d, hash->x, hash->len,
                  rnd_buffer_rand, &rnd_info ) == result );

     if ( result == 0)
     {
         TEST_ASSERT( mbedtls_mpi_cmp_mpi( &r, &r_check ) == 0 );
         TEST_ASSERT( mbedtls_mpi_cmp_mpi( &s, &s_check ) == 0 );

         TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, &r_check, &s_check ) == 0 );

         TEST_ASSERT( mbedtls_mpi_sub_int( &r, &r, 1 ) == 0 );
         TEST_ASSERT( mbedtls_mpi_add_int( &s, &s, 1 ) == 0 );

         TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len,
                      &Q, &r, &s_check ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
         TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len,
                      &Q, &r_check, &s ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
         TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len,
                      &grp.G, &r_check, &s_check ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
     }

 exit:
     mbedtls_ecp_group_free( &grp );
     mbedtls_ecp_point_free( &Q );
     mbedtls_mpi_free( &d ); mbedtls_mpi_free( &r ); mbedtls_mpi_free( &s );
     mbedtls_mpi_free( &r_check ); mbedtls_mpi_free( &s_check );
 }
 /* END_CASE */

 /* BEGIN_CASE depends_on:MBEDTLS_ECDSA_DETERMINISTIC */
 void ecdsa_det_test_vectors( int id, char * d_str, int md_alg, char * msg,
                              char * r_str, char * s_str )
 {
     mbedtls_ecp_group grp;
     mbedtls_mpi d, r, s, r_check, s_check;
     unsigned char hash[MBEDTLS_MD_MAX_SIZE];
     size_t hlen;
     const mbedtls_md_info_t *md_info;

     mbedtls_ecp_group_init( &grp );
     mbedtls_mpi_init( &d ); mbedtls_mpi_init( &r ); mbedtls_mpi_init( &s );
     mbedtls_mpi_init( &r_check ); mbedtls_mpi_init( &s_check );
     memset( hash, 0, sizeof( hash ) );

     TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &d, 16, d_str ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &r_check, 16, r_str ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &s_check, 16, s_str ) == 0 );

     md_info = mbedtls_md_info_from_type( md_alg );
     TEST_ASSERT( md_info != NULL );
     hlen = mbedtls_md_get_size( md_info );
     TEST_ASSERT( mbedtls_md( md_info, (const unsigned char *) msg,
                  strlen( msg ), hash ) == 0 );

     TEST_ASSERT( mbedtls_ecdsa_sign_det( &grp, &r, &s, &d, hash, hlen, md_alg ) == 0 );

     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &r, &r_check ) == 0 );
     TEST_ASSERT( mbedtls_mpi_cmp_mpi( &s, &s_check ) == 0 );

 exit:
     mbedtls_ecp_group_free( &grp );
     mbedtls_mpi_free( &d ); mbedtls_mpi_free( &r ); mbedtls_mpi_free( &s );
     mbedtls_mpi_free( &r_check ); mbedtls_mpi_free( &s_check );
 }
 /* END_CASE */

 /* BEGIN_CASE depends_on:MBEDTLS_SHA256_C */
 void ecdsa_write_read_random( int id )
 {
     mbedtls_ecdsa_context ctx;
     rnd_pseudo_info rnd_info;
     unsigned char hash[32];
     unsigned char sig[200];
     size_t sig_len, i;

     mbedtls_ecdsa_init( &ctx );
     memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );
     memset( hash, 0, sizeof( hash ) );
     memset( sig, 0x2a, sizeof( sig ) );

     /* prepare material for signature */
     TEST_ASSERT( rnd_pseudo_rand( &rnd_info, hash, sizeof( hash ) ) == 0 );

     /* generate signing key */
     TEST_ASSERT( mbedtls_ecdsa_genkey( &ctx, id, &rnd_pseudo_rand, &rnd_info ) == 0 );

     /* generate and write signature, then read and verify it */
     TEST_ASSERT( mbedtls_ecdsa_write_signature( &ctx, MBEDTLS_MD_SHA256,
                  hash, sizeof( hash ),
                  sig, &sig_len, &rnd_pseudo_rand, &rnd_info ) == 0 );
     TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
                  sig, sig_len ) == 0 );

     /* check we didn't write past the announced length */
     for( i = sig_len; i < sizeof( sig ); i++ )
         TEST_ASSERT( sig[i] == 0x2a );

     /* try verification with invalid length */
     TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
                  sig, sig_len - 1 ) != 0 );
     TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
                  sig, sig_len + 1 ) != 0 );

     /* try invalid sequence tag */
     sig[0]++;
     TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
                  sig, sig_len ) != 0 );
     sig[0]--;

     /* try modifying r */
     sig[10]++;
     TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
                  sig, sig_len ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
     sig[10]--;

     /* try modifying s */
     sig[sig_len - 1]++;
     TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
                  sig, sig_len ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
     sig[sig_len - 1]--;

 exit:
     mbedtls_ecdsa_free( &ctx );
 }
 /* END_CASE */

 /* BEGIN_CASE depends_on:MBEDTLS_ECP_RESTARTABLE */
 void ecdsa_read_restart( int id, char *k_str, char *h_str, char *s_str,
                          int max_ops, int min_restart, int max_restart )
 {
     mbedtls_ecdsa_context ctx;
     mbedtls_ecdsa_restart_ctx rs_ctx;
     unsigned char hash[64];
     unsigned char sig[200];
     unsigned char pk[65];
     size_t sig_len, hash_len, pk_len;
     int ret, cnt_restart;

     mbedtls_ecdsa_init( &ctx );
     mbedtls_ecdsa_restart_init( &rs_ctx );

     hash_len = unhexify(hash, h_str);
     sig_len = unhexify(sig, s_str);
     pk_len = unhexify(pk, k_str);

     TEST_ASSERT( mbedtls_ecp_group_load( &ctx.grp, id ) == 0 );
     TEST_ASSERT( mbedtls_ecp_point_read_binary( &ctx.grp, &ctx.Q, pk, pk_len ) == 0 );

     mbedtls_ecp_set_max_ops( max_ops );

     cnt_restart = 0;
     do {
         ret = mbedtls_ecdsa_read_signature_restartable( &ctx,
                             hash, hash_len, sig, sig_len, &rs_ctx );
     } 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 );

     /* try modifying r */
     sig[10]++;
     do {
         ret = mbedtls_ecdsa_read_signature_restartable( &ctx,
                             hash, hash_len, sig, sig_len, &rs_ctx );
     } while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
     TEST_ASSERT( ret == MBEDTLS_ERR_ECP_VERIFY_FAILED );
     sig[10]--;

     /* try modifying s */
     sig[sig_len - 1]++;
     do {
         ret = mbedtls_ecdsa_read_signature_restartable( &ctx,
                             hash, hash_len, sig, sig_len, &rs_ctx );
     } while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
     TEST_ASSERT( ret == MBEDTLS_ERR_ECP_VERIFY_FAILED );
     sig[sig_len - 1]--;

     /* Do we leak memory when aborting an operation?
      * This test only makes sense when we actually restart */
     if( min_restart > 0 )
     {
         ret = mbedtls_ecdsa_read_signature_restartable( &ctx,
                             hash, hash_len, sig, sig_len, &rs_ctx );
         TEST_ASSERT( ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
     }

 exit:
     mbedtls_ecdsa_free( &ctx );
     mbedtls_ecdsa_restart_free( &rs_ctx );
 }
 /* END_CASE */

 /* BEGIN_CASE depends_on:MBEDTLS_ECP_RESTARTABLE:MBEDTLS_ECDSA_DETERMINISTIC */
 void ecdsa_write_restart( int id, char *d_str, int md_alg,
                           char *msg, char *sig_str,
                           int max_ops, int min_restart, int max_restart )
 {
     int ret, cnt_restart;
     mbedtls_ecdsa_restart_ctx rs_ctx;
     mbedtls_ecdsa_context ctx;
     unsigned char hash[MBEDTLS_MD_MAX_SIZE];
     unsigned char sig[MBEDTLS_ECDSA_MAX_LEN];
     unsigned char sig_check[MBEDTLS_ECDSA_MAX_LEN];
     size_t hlen, slen, slen_check;
     const mbedtls_md_info_t *md_info;

     mbedtls_ecdsa_restart_init( &rs_ctx );
     mbedtls_ecdsa_init( &ctx );
     memset( hash, 0, sizeof( hash ) );
     memset( sig, 0, sizeof( sig ) );
     memset( sig_check, 0, sizeof( sig_check ) );

     TEST_ASSERT( mbedtls_ecp_group_load( &ctx.grp, id ) == 0 );
     TEST_ASSERT( mbedtls_mpi_read_string( &ctx.d, 16, d_str ) == 0 );
     slen_check = unhexify( sig_check, sig_str );

     md_info = mbedtls_md_info_from_type( md_alg );
     TEST_ASSERT( md_info != NULL );

     hlen = mbedtls_md_get_size( md_info );
     mbedtls_md( md_info, (const unsigned char *) msg, strlen( msg ), hash );

     mbedtls_ecp_set_max_ops( max_ops );

     slen = sizeof( sig );
     cnt_restart = 0;
     do {
         ret = mbedtls_ecdsa_write_signature_restartable( &ctx,
                 md_alg, hash, hlen, sig, &slen, NULL, NULL, &rs_ctx );
     } while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

     TEST_ASSERT( ret == 0 );
     TEST_ASSERT( slen == slen_check );
     TEST_ASSERT( memcmp( sig, sig_check, slen ) == 0 );

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

     /* Do we leak memory when aborting an operation?
      * This test only makes sense when we actually restart */
     if( min_restart > 0 )
     {
         ret = mbedtls_ecdsa_write_signature_restartable( &ctx,
                 md_alg, hash, hlen, sig, &slen, NULL, NULL, &rs_ctx );
         TEST_ASSERT( ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
     }

 exit:
     mbedtls_ecdsa_restart_free( &rs_ctx );
     mbedtls_ecdsa_free( &ctx );
 }
 /* END_CASE */
	/* BEGIN_HEADER */
	#include "mbedtls/ecdsa.h"
	/* END_HEADER */

	/* BEGIN_DEPENDENCIES
	* depends_on:MBEDTLS_ECDSA_C
	* END_DEPENDENCIES
	*/

	/* BEGIN_CASE */
	void ecdsa_prim_random( int id )
	{
	mbedtls_ecp_group grp;
	mbedtls_ecp_point Q;
	mbedtls_mpi d, r, s;
	rnd_pseudo_info rnd_info;
	unsigned char buf[MBEDTLS_MD_MAX_SIZE];

	mbedtls_ecp_group_init( &grp );
	mbedtls_ecp_point_init( &Q );
	mbedtls_mpi_init( &d ); mbedtls_mpi_init( &r ); mbedtls_mpi_init( &s );
	memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );
	memset( buf, 0, sizeof( buf ) );

	/* prepare material for signature */
	TEST_ASSERT( rnd_pseudo_rand( &rnd_info, buf, sizeof( buf ) ) == 0 );
	TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
	TEST_ASSERT( mbedtls_ecp_gen_keypair( &grp, &d, &Q, &rnd_pseudo_rand, &rnd_info )
	== 0 );

	TEST_ASSERT( mbedtls_ecdsa_sign( &grp, &r, &s, &d, buf, sizeof( buf ),
	&rnd_pseudo_rand, &rnd_info ) == 0 );
	TEST_ASSERT( mbedtls_ecdsa_verify( &grp, buf, sizeof( buf ), &Q, &r, &s ) == 0 );

	exit:
	mbedtls_ecp_group_free( &grp );
	mbedtls_ecp_point_free( &Q );
	mbedtls_mpi_free( &d ); mbedtls_mpi_free( &r ); mbedtls_mpi_free( &s );
	}
	/* END_CASE */

	/* BEGIN_CASE */
	void ecdsa_prim_test_vectors( int id, char * d_str, char * xQ_str,
	char * yQ_str, data_t * rnd_buf,
	data_t * hash, char * r_str, char * s_str,
	int result )
	{
	mbedtls_ecp_group grp;
	mbedtls_ecp_point Q;
	mbedtls_mpi d, r, s, r_check, s_check;
	rnd_buf_info rnd_info;

	mbedtls_ecp_group_init( &grp );
	mbedtls_ecp_point_init( &Q );
	mbedtls_mpi_init( &d ); mbedtls_mpi_init( &r ); mbedtls_mpi_init( &s );
	mbedtls_mpi_init( &r_check ); mbedtls_mpi_init( &s_check );

	TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
	TEST_ASSERT( mbedtls_ecp_point_read_string( &Q, 16, xQ_str, yQ_str ) == 0 );
	TEST_ASSERT( mbedtls_mpi_read_string( &d, 16, d_str ) == 0 );
	TEST_ASSERT( mbedtls_mpi_read_string( &r_check, 16, r_str ) == 0 );
	TEST_ASSERT( mbedtls_mpi_read_string( &s_check, 16, s_str ) == 0 );
	rnd_info.buf = rnd_buf->x;
	rnd_info.length = rnd_buf->len;

	/* Fix rnd_buf->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.length - 1; i++ )
	rnd_buf->x[i] = rnd_buf->x[i] << shift \| rnd_buf->x[i+1] >> ( 8 - shift );

	rnd_buf->x[rnd_info.length-1] <<= shift;
	}

	TEST_ASSERT( mbedtls_ecdsa_sign( &grp, &r, &s, &d, hash->x, hash->len,
	rnd_buffer_rand, &rnd_info ) == result );

	if ( result == 0)
	{
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &r, &r_check ) == 0 );
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &s, &s_check ) == 0 );

	TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len, &Q, &r_check, &s_check ) == 0 );

	TEST_ASSERT( mbedtls_mpi_sub_int( &r, &r, 1 ) == 0 );
	TEST_ASSERT( mbedtls_mpi_add_int( &s, &s, 1 ) == 0 );

	TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len,
	&Q, &r, &s_check ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
	TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len,
	&Q, &r_check, &s ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
	TEST_ASSERT( mbedtls_ecdsa_verify( &grp, hash->x, hash->len,
	&grp.G, &r_check, &s_check ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
	}

	exit:
	mbedtls_ecp_group_free( &grp );
	mbedtls_ecp_point_free( &Q );
	mbedtls_mpi_free( &d ); mbedtls_mpi_free( &r ); mbedtls_mpi_free( &s );
	mbedtls_mpi_free( &r_check ); mbedtls_mpi_free( &s_check );
	}
	/* END_CASE */

	/* BEGIN_CASE depends_on:MBEDTLS_ECDSA_DETERMINISTIC */
	void ecdsa_det_test_vectors( int id, char * d_str, int md_alg, char * msg,
	char * r_str, char * s_str )
	{
	mbedtls_ecp_group grp;
	mbedtls_mpi d, r, s, r_check, s_check;
	unsigned char hash[MBEDTLS_MD_MAX_SIZE];
	size_t hlen;
	const mbedtls_md_info_t *md_info;

	mbedtls_ecp_group_init( &grp );
	mbedtls_mpi_init( &d ); mbedtls_mpi_init( &r ); mbedtls_mpi_init( &s );
	mbedtls_mpi_init( &r_check ); mbedtls_mpi_init( &s_check );
	memset( hash, 0, sizeof( hash ) );

	TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
	TEST_ASSERT( mbedtls_mpi_read_string( &d, 16, d_str ) == 0 );
	TEST_ASSERT( mbedtls_mpi_read_string( &r_check, 16, r_str ) == 0 );
	TEST_ASSERT( mbedtls_mpi_read_string( &s_check, 16, s_str ) == 0 );

	md_info = mbedtls_md_info_from_type( md_alg );
	TEST_ASSERT( md_info != NULL );
	hlen = mbedtls_md_get_size( md_info );
	TEST_ASSERT( mbedtls_md( md_info, (const unsigned char *) msg,
	strlen( msg ), hash ) == 0 );

	TEST_ASSERT( mbedtls_ecdsa_sign_det( &grp, &r, &s, &d, hash, hlen, md_alg ) == 0 );

	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &r, &r_check ) == 0 );
	TEST_ASSERT( mbedtls_mpi_cmp_mpi( &s, &s_check ) == 0 );

	exit:
	mbedtls_ecp_group_free( &grp );
	mbedtls_mpi_free( &d ); mbedtls_mpi_free( &r ); mbedtls_mpi_free( &s );
	mbedtls_mpi_free( &r_check ); mbedtls_mpi_free( &s_check );
	}
	/* END_CASE */

	/* BEGIN_CASE depends_on:MBEDTLS_SHA256_C */
	void ecdsa_write_read_random( int id )
	{
	mbedtls_ecdsa_context ctx;
	rnd_pseudo_info rnd_info;
	unsigned char hash[32];
	unsigned char sig[200];
	size_t sig_len, i;

	mbedtls_ecdsa_init( &ctx );
	memset( &rnd_info, 0x00, sizeof( rnd_pseudo_info ) );
	memset( hash, 0, sizeof( hash ) );
	memset( sig, 0x2a, sizeof( sig ) );

	/* prepare material for signature */
	TEST_ASSERT( rnd_pseudo_rand( &rnd_info, hash, sizeof( hash ) ) == 0 );

	/* generate signing key */
	TEST_ASSERT( mbedtls_ecdsa_genkey( &ctx, id, &rnd_pseudo_rand, &rnd_info ) == 0 );

	/* generate and write signature, then read and verify it */
	TEST_ASSERT( mbedtls_ecdsa_write_signature( &ctx, MBEDTLS_MD_SHA256,
	hash, sizeof( hash ),
	sig, &sig_len, &rnd_pseudo_rand, &rnd_info ) == 0 );
	TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
	sig, sig_len ) == 0 );

	/* check we didn't write past the announced length */
	for( i = sig_len; i < sizeof( sig ); i++ )
	TEST_ASSERT( sig[i] == 0x2a );

	/* try verification with invalid length */
	TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
	sig, sig_len - 1 ) != 0 );
	TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
	sig, sig_len + 1 ) != 0 );

	/* try invalid sequence tag */
	sig[0]++;
	TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
	sig, sig_len ) != 0 );
	sig[0]--;

	/* try modifying r */
	sig[10]++;
	TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
	sig, sig_len ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
	sig[10]--;

	/* try modifying s */
	sig[sig_len - 1]++;
	TEST_ASSERT( mbedtls_ecdsa_read_signature( &ctx, hash, sizeof( hash ),
	sig, sig_len ) == MBEDTLS_ERR_ECP_VERIFY_FAILED );
	sig[sig_len - 1]--;

	exit:
	mbedtls_ecdsa_free( &ctx );
	}
	/* END_CASE */

	/* BEGIN_CASE depends_on:MBEDTLS_ECP_RESTARTABLE */
	void ecdsa_read_restart( int id, char k_str, char h_str, char *s_str,
	int max_ops, int min_restart, int max_restart )
	{
	mbedtls_ecdsa_context ctx;
	mbedtls_ecdsa_restart_ctx rs_ctx;
	unsigned char hash[64];
	unsigned char sig[200];
	unsigned char pk[65];
	size_t sig_len, hash_len, pk_len;
	int ret, cnt_restart;

	mbedtls_ecdsa_init( &ctx );
	mbedtls_ecdsa_restart_init( &rs_ctx );

	hash_len = unhexify(hash, h_str);
	sig_len = unhexify(sig, s_str);
	pk_len = unhexify(pk, k_str);

	TEST_ASSERT( mbedtls_ecp_group_load( &ctx.grp, id ) == 0 );
	TEST_ASSERT( mbedtls_ecp_point_read_binary( &ctx.grp, &ctx.Q, pk, pk_len ) == 0 );

	mbedtls_ecp_set_max_ops( max_ops );

	cnt_restart = 0;
	do {
	ret = mbedtls_ecdsa_read_signature_restartable( &ctx,
	hash, hash_len, sig, sig_len, &rs_ctx );
	} 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 );

	/* try modifying r */
	sig[10]++;
	do {
	ret = mbedtls_ecdsa_read_signature_restartable( &ctx,
	hash, hash_len, sig, sig_len, &rs_ctx );
	} while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
	TEST_ASSERT( ret == MBEDTLS_ERR_ECP_VERIFY_FAILED );
	sig[10]--;

	/* try modifying s */
	sig[sig_len - 1]++;
	do {
	ret = mbedtls_ecdsa_read_signature_restartable( &ctx,
	hash, hash_len, sig, sig_len, &rs_ctx );
	} while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
	TEST_ASSERT( ret == MBEDTLS_ERR_ECP_VERIFY_FAILED );
	sig[sig_len - 1]--;

	/* Do we leak memory when aborting an operation?
	* This test only makes sense when we actually restart */
	if( min_restart > 0 )
	{
	ret = mbedtls_ecdsa_read_signature_restartable( &ctx,
	hash, hash_len, sig, sig_len, &rs_ctx );
	TEST_ASSERT( ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
	}

	exit:
	mbedtls_ecdsa_free( &ctx );
	mbedtls_ecdsa_restart_free( &rs_ctx );
	}
	/* END_CASE */

	/* BEGIN_CASE depends_on:MBEDTLS_ECP_RESTARTABLE:MBEDTLS_ECDSA_DETERMINISTIC */
	void ecdsa_write_restart( int id, char *d_str, int md_alg,
	char msg, char sig_str,
	int max_ops, int min_restart, int max_restart )
	{
	int ret, cnt_restart;
	mbedtls_ecdsa_restart_ctx rs_ctx;
	mbedtls_ecdsa_context ctx;
	unsigned char hash[MBEDTLS_MD_MAX_SIZE];
	unsigned char sig[MBEDTLS_ECDSA_MAX_LEN];
	unsigned char sig_check[MBEDTLS_ECDSA_MAX_LEN];
	size_t hlen, slen, slen_check;
	const mbedtls_md_info_t *md_info;

	mbedtls_ecdsa_restart_init( &rs_ctx );
	mbedtls_ecdsa_init( &ctx );
	memset( hash, 0, sizeof( hash ) );
	memset( sig, 0, sizeof( sig ) );
	memset( sig_check, 0, sizeof( sig_check ) );

	TEST_ASSERT( mbedtls_ecp_group_load( &ctx.grp, id ) == 0 );
	TEST_ASSERT( mbedtls_mpi_read_string( &ctx.d, 16, d_str ) == 0 );
	slen_check = unhexify( sig_check, sig_str );

	md_info = mbedtls_md_info_from_type( md_alg );
	TEST_ASSERT( md_info != NULL );

	hlen = mbedtls_md_get_size( md_info );
	mbedtls_md( md_info, (const unsigned char *) msg, strlen( msg ), hash );

	mbedtls_ecp_set_max_ops( max_ops );

	slen = sizeof( sig );
	cnt_restart = 0;
	do {
	ret = mbedtls_ecdsa_write_signature_restartable( &ctx,
	md_alg, hash, hlen, sig, &slen, NULL, NULL, &rs_ctx );
	} while( ret == MBEDTLS_ERR_ECP_IN_PROGRESS && ++cnt_restart );

	TEST_ASSERT( ret == 0 );
	TEST_ASSERT( slen == slen_check );
	TEST_ASSERT( memcmp( sig, sig_check, slen ) == 0 );

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

	/* Do we leak memory when aborting an operation?
	* This test only makes sense when we actually restart */
	if( min_restart > 0 )
	{
	ret = mbedtls_ecdsa_write_signature_restartable( &ctx,
	md_alg, hash, hlen, sig, &slen, NULL, NULL, &rs_ctx );
	TEST_ASSERT( ret == MBEDTLS_ERR_ECP_IN_PROGRESS );
	}

	exit:
	mbedtls_ecdsa_restart_free( &rs_ctx );
	mbedtls_ecdsa_free( &ctx );
	}
	/* END_CASE */