RadiusRB, a ruby RADIUS client library that supports: Authentication, Accounting, Custom dictionaries and Vendor Specific Attributes.

Rack middleware to acquire authentication information froma "Stanford WebAuth system.

Protect a page's contents with HTTP Basic Authentication.

A gem to generate Rails application templates you can use to create Rails starter apps that use Devise for authentication.

Mori is a lightweight module based authentication platform. Mori uses Warden for session management, and is intended to be easy to overwrite, and configurable.

Ruby implementation of the DigiID authentication protocol

rb-airgram provides a convenient wrapper around all of the current AirGram API methods, including those that require authentication.

Ruby gem for StrongMind authentication in a strongmind app

Integrate Monk ID authentication and single sign-on for apps and websites on the server-side.

Mongoid is an ODM (Object Document Mapper) Framework for MongoDB, written in Ruby. This version supports authentication to MongoDB with username and password

MojoAuth is a set of standard approaches to cross-app authentication based on HMAC.

Includes 3 generators, the first two are to create a Rails authentication. The last one is to add bootstrap to a rails application

This widely-used plugin provides a foundation for securely managing user.

Generates Rails code implementing a model security and authentication system for your Rails app.

Firebase Authentication for Ruby client

Authentication, Registrations, Confirmations, Invitations etc for Padrino

Authentication and authorization for Revelry toolkit apps using Devise, Rolify and Pundit.

Ruby OpenID Test Server (ROST) provides a basic OpenID server made in top of the Rack gem. With this small server, you can make dummy OpenID request for testing purposes, the success of the response will depend on a parameter given on the url of the authentication request.

OAuth2 (Facebook Connect) authentication strategy for connecting to lds.org thru LDS Connect with Ruby / Sinatra / etc

Low level Rack authentication enforcement