IAuthU provides a basic iTunes U authentication server, along with libraries for building iTunes U authentication servers into your own application.

Merb plugin that provides authentication support

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

Generates Rails code for an authentication system and persistent cookie management.

This extension provides PAM - Pluggable Authentication Modules - integration

A gem providing HMAC based authentication for HTTP

Your friendly, cigar smoking authentication dicator... From Space!

A rails plugin that handles authentication

Simple, complete Rails authentication scheme.

A collection of useful Rails generator scripts for scaffolding, layout files, authentication, and more.

Rails authentication with email & password.

Simple admin function for Rails authentication.

An Authentication framework for Merb

Rails authentication done right

An unobtrusive ruby authentication library based on ActiveRecord.

a restfull_authentication diamond for mr_henry

Client library for the Central Authentication Service (CAS) protocol. (this version specially prepared for echologic)

Client library for the Central Authentication Service (CAS) protocol, modified to work with Indiana University's CAS server.

Merb Slice adds quick DB'less OpenID authentication to your app

Easy RESTful authentication + authorization.