Re-blogged from wildcardcorp.com
Factored is comprehensive 2-factor authentication open source project sponsored by Wildcard corp. It's primary design is to protect the entire web application, any web application, where users are not allowed any access until they authenticate 1-factor of authentication which is provided by factored. The second factor of authentication will be provided by the web app, which is usually is a normal login with username and password.
Factored uses a plugin system to provide different types of authorizations. Out of the box, it provides Google Authenticator and Email Token support.
Factored supports different types of integrations for your web applications.
Proxy: factor is in front of web application and sends authorized requests to configured web application. Web server plugins: Nginx and ATS plugins are available using lua. WSGI: A filter is provided to be use with Python Web Applications that utilize this standard.
Check out the docs for more information.