SAML
Security Assertion Markup Language
Providers Implémentations
SimpleSAMLphp
https://simplesamlphp.org/
SAML 2.0 as a Service Provider (SP)
SAML 2.0 as an Identity Provider (IdP)
it also supports some other identity protocols and frameworks, such as Shibboleth 1.3, A-Select, CAS, OpenID, WS-Federation or OAuth, and is easily extendable
LemonLDAP::NG
LemonLDAP::NG offers a full AAA (Authentication Authorization Accounting) protection:
Authentication: credentials are needed to open SSO session
Authorization: access rules are checked for every HTTP requests
Accounting: each access is logged
Authentic2
Shibboleth
OpenAM
Libraries
Lasso
OpenSAML
Dokuwiki plugins for SAML