--- aes/aes.install.orig	2009-04-16 23:10:06.000000000 -0700
+++ aes/aes.install	2009-04-16 23:11:36.000000000 -0700
@@ -1,6 +1,17 @@
 <?php
 // $Id $
 
+function aes_requirements($phase) {
+  return array(
+    array(
+      'title' => 'mcrypt PHP module',
+      //'value' => '', -- do we require a minimum version?
+      'description' => 'The Drupal AES module requires the PHP module named mcrypt.',
+      'severity' => (extension_loaded("mcrypt") === false ? REQUIREMENT_ERROR : REQUIREMENT_OK),
+    )
+  );
+}
+
 function aes_install() {
   
   drupal_install_schema("aes");