Method "FindApplicationKeys" of a Service can be called with NULL as credentials


Bug Description
If a data storage is published as WCF service it can be used from different applications. For administrative reasons it is useful to have a method to find out which application keys are used. Therefore the service class provides the method "FindApplicationKeys". To use it you must provide administrator credentials so that it could not be called from everyone using this service.
The bug is: if you provide NULL as credentials you will get the list of application keys

Requested Behaviour
If you provide NULL as credentials you should get an empty list