Strong yet simple Rails authentication?

My authentication system will be at the heart of my application and the revenue model for my business. I want a strong, but yet开发者_JAVA百科 simple authentication option for Rails.

What are your suggestions?

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You have many different authentification options for Rails.
I personaly prefer Devise, it's really complete, with a lot of features and simple to use.
You can have a look at a Railscast : http://railscasts.com/episodes/209-introducing-devise

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Use facebook for websites to authenticate use. There is one one gem which lets you use facebook auth via devise (devise_facebook_connectable) https://github.com/grimen/devise_facebook_connectable