@@ -141,8 +141,19 @@
 	_outerHash = _innerHash = nil;
 
 	_outerHash = [_outerHashCopy copy];
 	_innerHash = [_innerHashCopy copy];
 
+	_calculated = false;
+}
+
+- (void)zero
+{
+	[_outerHash release];
+	[_innerHash release];
+	[_outerHashCopy release];
+	[_innerHashCopy release];
+	_outerHash = _innerHash = _outerHashCopy = _innerHashCopy = nil;
+
 	_calculated = false;
 }
 @end