diff --git a/lib/ClassBuilder.js b/lib/ClassBuilder.js
index 807ee55..5108227 100644
--- a/lib/ClassBuilder.js
+++ b/lib/ClassBuilder.js
@@ -148,6 +148,9 @@ function ClassBuilder( member_builder, visibility_factory )
  */
 exports.ClassBase = function Class() {};
 
+// the base class has the class identifier 0
+util.defineSecureProp( exports.ClassBase, '__cid', 0 );
+
 
 /**
  * Default static property method