Combine hex parameters in a struct
diff --git a/tests/suites/test_suite_ecdh.function b/tests/suites/test_suite_ecdh.function
index 0b88e65..2d71828 100644
--- a/tests/suites/test_suite_ecdh.function
+++ b/tests/suites/test_suite_ecdh.function
@@ -43,11 +43,9 @@
 /* END_CASE */
 
 /* BEGIN_CASE */
-void ecdh_primitive_testvec( int id, uint8_t * rnd_buf_A,
-                             uint32_t rnd_buf_A_len, char * xA_str,
-                             char * yA_str, uint8_t * rnd_buf_B,
-                             uint32_t rnd_buf_B_len, char * xB_str,
-                             char * yB_str, char * z_str )
+void ecdh_primitive_testvec( int id, HexParam_t * rnd_buf_A, char * xA_str,
+                             char * yA_str, HexParam_t * rnd_buf_B,
+                             char * xB_str, char * yB_str, char * z_str )
 {
     mbedtls_ecp_group grp;
     mbedtls_ecp_point qA, qB;
@@ -61,36 +59,36 @@
 
     TEST_ASSERT( mbedtls_ecp_group_load( &grp, id ) == 0 );
 
-    rnd_info_A.buf = rnd_buf_A;
-    rnd_info_A.length = rnd_buf_A_len;
+    rnd_info_A.buf = rnd_buf_A->x;
+    rnd_info_A.length = rnd_buf_A->len;
 
-    /* Fix rnd_buf_A by shifting it left if necessary */
+    /* 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[i] = rnd_buf_A[i] << shift
-                         | rnd_buf_A[i+1] >> ( 8 - shift );
+            rnd_buf_A->x[i] = rnd_buf_A->x[i] << shift
+                         | rnd_buf_A->x[i+1] >> ( 8 - shift );
 
-        rnd_buf_A[rnd_info_A.length-1] <<= shift;
+        rnd_buf_A->x[rnd_info_A.length-1] <<= shift;
     }
 
-    rnd_info_B.buf = rnd_buf_B;
-    rnd_info_B.length = rnd_buf_B_len;
+    rnd_info_B.buf = rnd_buf_B->x;
+    rnd_info_B.length = rnd_buf_B->len;
 
-    /* Fix rnd_buf_B by shifting it left if necessary */
+    /* 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[i] = rnd_buf_B[i] << shift
-                         | rnd_buf_B[i+1] >> ( 8 - shift );
+            rnd_buf_B->x[i] = rnd_buf_B->x[i] << shift
+                         | rnd_buf_B->x[i+1] >> ( 8 - shift );
 
-        rnd_buf_B[rnd_info_B.length-1] <<= shift;
+        rnd_buf_B->x[rnd_info_B.length-1] <<= shift;
     }
 
     TEST_ASSERT( mbedtls_ecdh_gen_public( &grp, &dA, &qA,