The tested, trusted and most secure single sign on protocol on the web is the Central Authentication Service (CAS).
While just imputing your details such as user ID and password just once you can access numerous applications. It permits web applications to verify users without revealing users confidential details such as passwords.
The CAS is also known as a software package that implements the single sign-on and LogicalDOC integreates itself with it.
For more information see the Manual Page.