LemonLDAP::NG is a full open source WebSSO product.

It supports a lot af authentication backends :

• LDAP
• SSL
• Kerberos
• CAS
• DBI
• Liberty Alliance
• SAMLv2
• OpenID
• Twitter

SimpleSAMLphp is a simple application written in native PHP that deals with authentication. SimpleSAMLphp supports several federation protocols, authentication mechanisms and can be used both for local authentication, as a service provider or as an identity provider. simpleSAMLphp can even be used to bridge other federation protocols, in example allowing you to setup a Shibboleth 1.3 Service Provider in a SAML 2.0 Federation (or the other way around).

A flexible and comprehensive open source, cross-domain, attribute-based web single-sign on system based on SAML 1.x and 2.0. Built on the OpenSAML libraries, a Java-based identity provider and native (C++) service provider are provided. The identity provider supports pluggability of both authentication and attribute sources and supports most of the core SAML SSO profiles and bindings. The service provider supports most popular web servers and enables seamless and loosely coupled integration of authentication and attribute data with applications without programming to product-specific APIs.

Open source libraries in Java and C++ providing core message, binding, and profile classes for implementing applications based on SAML 1.0, 1.1, and 2.0. Extensive design integration with the native Java and C++ programming models is provided. OpenSAML is a low-level toolkit that does not by itself implement full SAML profiles such as single sign-on, but can be used to simplify the implementation of such profiles. Provided under the standard Apache 2.0 license for use in any commercial or non-commercial code.

ZXID.org Identity Management toolkit implements standalone SAML 2.0 and Liberty ID-WSF 2.0 stacks. It is a C implementation with minimal external dependencies - OpenSSL, CURL, and zlib - ensuring easy deployment (no DLLhell). Due to its small footprint and efficient and accurate schema driven implementation, it is suitable for embedded and high volume applications. Language bindings to all popular highlevel languages such as PHP, Perl, and Java, are provided via SWIG. ZXID implements, as of July 07, SP, WSC, and WSP roles.