[eluser]WanWizard[/eluser]
The encrypted cookie only stores the session id, the IP address, the user agent string, and a timestamp.
It does not store any user data, since you're using the database for that.
The simplest thing is to store the user_id in the session. At the beginning of the page request, check if the id is present, and if so, retrieve the user. If that succeeds, the user is logged in.