Aikotoba is a Rails engine that makes it easy to implement simple email and password authentication.

Rails authentication with email & password.

Koinz clients require authentication via oauth koinz provider. They can also publish/subscribe for notifications in the koinz environment.

Generator that enabled LDAP authentication with a single command.

This this plugin for the leap platform provides user signup and login. It uses Secure Remote Password for the authentication.

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

Manages collecting of facebook authentication and provides helpers. It uses koala and is built for Rails 3.

add authentication to your website - in 1 minute or less.

Library utilizing IDCRL for Microsoft Windows Live ID authentication.

Locomotive plugin for adding basic authentication to pages of a site

Loginza - an interactive JavaScript widget provides visitors to your sites, a wide range of options for authentication through the accounts of common WEB-portals and services

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

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

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

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

Ruby gem for StrongMind authentication in a strongmind app

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

Authentication like merb, but for rails

Provides wrapper functionality and authentication for REST and RPC HTTP requests to OpenSocial-compliant endpoints, along with validation of incoming signed makeRequest calls.

Simple key/secret based authentication for apis