MYOB authentication strategy for OmniAuth

Use Google Apps as an Authentication Provider

Firebase Authentication wrapper for Ruby

Add AWS Signature 4 style authentication to grape API's.

MediaWiki::Butt provides a fully-featured interface to the MediaWiki API. It includes methods for changing wiki content, authentication, and queries.

Adds Kerberos authentication via libsasl to the MongoDB Ruby Driver on MRI and JRuby

This extension provides PAM - Pluggable Authentication Modules - integration

Gem for Rails application - provides you list of online users (for authentication gem 'devise')

omniauth provider for Microsoft V2 Authentication

A minimal dependency library for interacting with a Cerner OAuth 1.0a Access Token Service for invoking Cerner OAuth 1.0a protected services or implementing Cerner OAuth 1.0a authentication.

Basic Rails Framework files and assets for layout and authentication

Sinatra extension for user authentication with browserid.org

Simple, instant HTTP Basic Authentication for applications using Clearance.

Rails authentication framework using Mozilla Persona and the BrowserID protocol.

dynamoid-devise is flexible authentication solution for Rails 4.1.x with Warden using dynamoid as ORM...

A Ruby on Rails engine for authentication with Dailycred.

Mozilla BrowserID/Persona authentication module that works with Rails 3.1+ and Devise 2.1+

Ember-auth is an authentication framework for ember.js. It is expected to work out of the box with rails + devise.

Use phpbb for authentication in your rails app

Rack middleware for using the Authorization header with token authentication