I'm having a little problem. I am developing an application in PHP that is divided into modules. Each module is completely independent, is on a separate server and has an own domain. eg:
www.moduloprincipal.com.br, www.modulo2.com.br, www.modulo3.com.br, etc ...
The problem is that I need that when a user to authenticate to one of the modules (either) the user can access the same user other modules without having to authenticate again.
Currently each application is on a different server, but if necessary they are in the same server, it would not be a problem.
IMPORTANT:
Read several threads, but found no solution really safe. Will be interesting to use OAuth?
Currently the application uses $ _SESSION to authenticate users, but you can use $ _COOKIE smoothly.
I'm using CodeIgniter
Translated by Google Translate. Sorry ...