These are all implementations of single sign-on:
- AccessMatrix USO (by i-Sprint Innovations)
- Microsoft Active Directory Federation Services (ADFS) claims-based system and application federation
- Athens access and identity management
- Avaya SSO
- CA SiteMinder (formerly Netegrity SiteMinder)
- Central Authentication Service (CAS)
- COMA
- CoSign
- Distributed Access Control System (DACS)
- Enterprise Sign On Engine
- Evidian Enterprise SSO
- Facebook connect
- Microsoft Forefront Identity Manager (FIM) state-based identity life-cycle management
- FreeIPA
- Geneous Software
- Global Login System
- Imprivata OneSign (Enterprise single sign-on and strong authentication)
- ionisis (Core Account Authentication - single sign-on; allows users to login to any participating website, without the need to register an account first)
- JBoss SSO
- JOSSO (Open Source Single Sign-On Server)
- JsonSSO (Single Sign-On specifically for Ajax web applications using JSON messages)
- Kerberos
- LTPA
- myOneLogin (Secure single sign-on for the cloud)
- OneLogin (single sign-on and user provisioning for the cloud)
- OpenAM (previously OpenSSO)
- OpenASelect
- Oracle Access Manager
- Passlogix
- Pubcookie
- SAML
- Secure Network Communications
- Shibboleth
- Smart card
- Tiger OneConnect
- Ubuntu Single Sign On (OpenID-based single sign on service)
- Windows Live ID