Thanks grandaCoder, you are correct in a way because they way we have designed our application , is to cache the permissions on the client side as well, so yes the first time the service call will get all permissions from the service side cache and then point forward use the client side cache.
Also, the object is to do operation based authorization and hence the reason I just want to Cache all operations a user is allowed to perform. Is there a way to retrieve just all user allowed operations?