FIDO® Certified StrongKey FIDO Server (SKFS)
PHP strong authentication library, web interface & CLI, OATH certified
nuBuilder Forte is a cloud database builder.
apache cookie SSO mechanism.
PHP User Login and Management System based on Codeigniter
Two-factor authentication system
phpbb Multiple domain Single Sign on with wordpress plugin
Deprecated project - see http://wordpress.org/extend/plugins/wpmuldap/