Create an own "OpenID-like system" Provider

I know th开发者_JAVA百科at Facebook use their own OpenID-like system called "Facebook connect", which you can use to authenticate users on your site, among other features.

In my case I have multiple Ruby on Rails applications:

• users.example.com
• profiles.example.com
• photos.example.com
• ...

I would like to use 'users.example.com' as a web service that allows users to authenticate to all my other applications the same way as works "Facebook connect" or OpenID. In few words, 'users.example.com' must works as a "OpenID-like system" for my applications in 'example.com'.

Can anyone give me tips and links to some useful resources?

P.S.: since I am a newbie in this matter, I do not know if I'm saying things that make sense. So someone could help me to understand (if I am wrong) ...

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Facebook is using OAuth 2.0 and this is now more popular than openid. You can see how to implement it on railcasts or search for "oauth rails" and you will geht enough info about it.

In my opinion this is the thing you are looking for.