diff --git a/sys/persistent.py b/sys/persistent.py
index 7e4acca..eac50b1 100644
--- a/sys/persistent.py
+++ b/sys/persistent.py
@@ -1,4 +1,5 @@
 import shelve
+import base64
 from threading import Lock
 
 class PersistentContainer(object):
@@ -83,6 +84,7 @@ class PersistentContainer(object):
 
 	def __getitem__(self, name):	
 		key = name+"."+self.namespace
+		key = base64.b64encode(key)
 		if key in self.dic:
 			return self.dic[key]
 		return None
@@ -103,17 +105,20 @@ class PersistentContainer(object):
 
 	def __contains__(self,name):
 		key = name+"."+self.namespace
+		key = base64.b64encode(key)
 		return key in self.dic
 
 	def _write(self):
 		for name in self.trans_cache.keys():		
 			key = name+"."+self.namespace
+			key = base64.b64encode(key)
 			val = self.trans_cache[name]
 			self.dic[key]=val
 			del self.trans_cache[name]
 		while len(self.trans_del):
 			name = self.trans_del.pop()
 			key = name+"."+self.namespace
+			key = base64.b64encode(key)
 			del self.dic[key]
 		self.dic.sync()