Which is best for ACL?

[eluser]Rick Jolly[/eluser]
I probably don't understand your concern, but even if someone had access to your server and could look at the ACL, what harm would that do? It is more important to protect usernames/passwords. I think that if a stranger could access your server, then you have larger concerns.

EDIT:
Sorry, I think I understand now. You want to serialize the ACL object and store it in the database. In which case, if someone could access your database, they could transparently change the ACL to grant a user admin privileges for example. That would be a problem since you might not know about it. So I guess if the serialized ACL is a string, you could use the CI encryption library when getting/saving the ACL to the database.