diff --git a/src/page.c b/src/page.c
index 23a04a84..6aaef428 100644
--- a/src/page.c
+++ b/src/page.c
@@ -105,7 +105,7 @@ static bool mi_page_is_valid_init(mi_page_t* page) {
 bool _mi_page_is_valid(mi_page_t* page) {
   mi_assert_internal(mi_page_is_valid_init(page));
   #if MI_SECURE
-  mi_assert_internal(page->key != 0);
+  mi_assert_internal(page->keys[0] != 0);
   #endif
   if (mi_page_heap(page)!=NULL) {
     mi_segment_t* segment = _mi_page_segment(page);