Combine hex parameters in a struct
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index 5cc32ab..eed5183 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -9,11 +9,11 @@
  */
 
 /* BEGIN_CASE depends_on:MBEDTLS_SSL_DTLS_ANTI_REPLAY */
-void ssl_dtls_replay( char *prevs, char *new, int ret )
+void ssl_dtls_replay( HexParam_t * prevs, HexParam_t * new, int ret )
 {
+    uint32_t len = 0;
     mbedtls_ssl_context ssl;
     mbedtls_ssl_config conf;
-    char *end_prevs = prevs + strlen( prevs ) + 1;
 
     mbedtls_ssl_init( &ssl );
     mbedtls_ssl_config_init( &conf );
@@ -25,15 +25,14 @@
     TEST_ASSERT( mbedtls_ssl_setup( &ssl, &conf ) == 0 );
 
     /* Read previous record numbers */
-    for( ; end_prevs - prevs >= 13; prevs += 13 )
+    for( len = 0; len < prevs->len; len += 6 )
     {
-        prevs[12] = '\0';
-        unhexify( ssl.in_ctr + 2, prevs );
+        memcpy( ssl.in_ctr + 2, prevs->x + len, 6 );
         mbedtls_ssl_dtls_replay_update( &ssl );
     }
 
     /* Check new number */
-    unhexify( ssl.in_ctr + 2, new );
+    memcpy( ssl.in_ctr + 2, new->x, 6 );
     TEST_ASSERT( mbedtls_ssl_dtls_replay_check( &ssl ) == ret );
 
     mbedtls_ssl_free( &ssl );