diff --git a/lib/ClassBuilder.js b/lib/ClassBuilder.js
index 63e36f6..d7d1361 100644
--- a/lib/ClassBuilder.js
+++ b/lib/ClassBuilder.js
@@ -26,6 +26,7 @@
 
 var util    = require( './util' ),
     Warning = require( './warn' ).Warning,
+    Symbol  = require( './util/Symbol' ),
 
     hasOwn = Object.prototype.hasOwnProperty,
 
@@ -73,7 +74,18 @@ var util    = require( './util' ),
         '__construct': true,
         'toString':    true,
         '__toString':  true,
-    };
+    },
+
+    /**
+     * Symbol used to encapsulate internal data
+     *
+     * Note that this is intentionally generated *outside* the ClassBuilder
+     * instance; this ensures that it is properly encapsulated and will not
+     * be exposed on the Classbuilder instance (which would defeat the
+     * purpose).
+     */
+    _priv = Symbol()
+;
 
 
 /**
@@ -225,7 +237,7 @@ exports.getForcedPublicMethods = function()
  */
 exports.getMeta = function( cls )
 {
-    return cls.___$$meta$$ || {};
+    return ( cls[ _priv ] || {} ).meta || {};
 }
 
 
@@ -342,7 +354,7 @@ exports.prototype.build = function extend( _, __ )
     {
         throw Error(
             "Cannot extend final class " +
-                ( base.___$$meta$$.name || '(anonymous)' )
+                ( base[ _priv ].meta.name || '(anonymous)' )
         );
     }
 
@@ -799,16 +811,19 @@ function validateAbstract( ctor, cname, abstract_methods, auto )
  */
 exports.prototype.createCtor = function( cname, abstract_methods, members )
 {
-    // concrete class
+    var new_class;
+
     if ( abstract_methods.__length === 0 )
     {
-        return this.createConcreteCtor( cname, members );
+        new_class = this.createConcreteCtor( cname, members );
     }
-    // abstract class
     else
     {
-        return this.createAbstractCtor( cname );
+        new_class = this.createAbstractCtor( cname );
     }
+
+    new_class[ _priv ] = {};
+    return new_class;
 }
 
 
@@ -1239,21 +1254,27 @@ function createMeta( func, cparent )
     // copy the parent prototype's metadata if it exists (inherit metadata)
     if ( parent_meta )
     {
-        func.___$$meta$$ = util.clone( parent_meta, true );
+        func[ _priv ].meta = util.clone( parent_meta, true );
     }
     else
     {
         // create empty
-        func.___$$meta$$ = {
+        func[ _priv ].meta = {
             implemented: [],
         };
     }
 
+    // TODO: this should be done elsewhere
+    if ( !func.prototype[ _priv ] )
+    {
+        func.prototype[ _priv ] = {};
+    }
+
     // store the metadata in the prototype as well (inconsiderable overhead;
     // it's just a reference)
-    func.prototype.___$$meta$$ = func.___$$meta$$;
+    func.prototype[ _priv ].meta = func[ _priv ].meta;
 
-    return func.___$$meta$$;
+    return func[ _priv ].meta;
 }