1. The Tor Project's free software protects your privacy online. Site blocked? Email [mailto:[email protected]] for help downloading Tor Browser.

  2. Flexible authentication solution for Rails with Warden.

  3. Amazon Cognito lets you add user sign-up, sign-in, and access control to your web and mobile apps quickly and easily. It scales to millions of users and supports sign-in with social identity providers and enterprise identity providers via SAML 2.0.

  4. OmniAuth is a flexible authentication system utilizing Rack middleware.

  5. Passport is a software program for businesses that makes accounting a bit easier.

  6. Open Source Identity and Access Management for modern Applications and Services.

  7. September 2018 Update! Since 2015, Orfox has been the only mobile app recommended by the Tor Project to utilize the privacy protections of Tor on Android.

  8. OpenLDAP Software is an open source implementation of the Lightweight Directory Access Protocol.

  9. Powerful authentication, authorization, and user management for any application

  10. OAuth that just works. Integrate 100+ OAuth providers in minutes.

  11. Satellizer is a nd-to-end, token-based authentication module for AngularJS

  12. FreeRADIUS is responsible for authenticating one third of all users on the Internet.