Lockdown 0.4.6

“Lockdown is a authentication/authorization system for RubyOnRails
(ver 2.x). While Merb functionality is in place, it is not complete.
There
will be a release solely focused on getting the Merb functionality up to
par with Rails.”

(sudo gem install lockdown)

http://lockdown.rubyforge.org
http://groups.google.com/group/stonean_lockdown?hl=en
git://github.com/stonean/lockdown.git

– Jean-François (via Rails Talk)

Pour merb je prefere
http://github.com/BrianTheCoder/can_has_auth_core/tree/master
mais pas de version rails !!