Single Sign Out accross multiple domains

Question

Hi, I know there are very similar questions and answers posted. And I have used them for reference, but I would like to throw a specific case out there. A way to implement Single Sign Out / Single Log Out across multiple domains.

From what I read it looks like the only way is using a server to server service, ie. tracking users by verifying that they have access with the SSO server, every pageload.

What I mean by Single Sign Out is that a user signed on at multiple sites can sign out by clicking a link to sign out from the current site (and not be redirected to signout pages on all other sites)

I have looked at OpenID server, but I dont believe it can be extended to support this. SimpleSAMLphp looks like a better alternative.

Discuss

Answer 1

You should store sessions data in some shared storage like database/Memcache using session identificators like user1194_dj1kldkjawi1ljidsa (1194 - user id). So then if you need to Sign Out on all domains, you need just to delete from session storage all entries with keys like user1194_*