DotNetOpenAuth 

Adds an InfoCard button to your ASP.NET web application's login page via a simple ASP.NET control. InfoCards enhance user security while mitigating phishing attacks by removing the need for a password... More information

Adds an InfoCard button to an OpenID relying party's login button panel. InfoCards enhance user security while mitigating phishing attacks by removing the need for a password credential or 3rd party... More information

Protect your users' data while allowing them to programmatically access it, including from other web applications, all without disclosing their login credential with you to 3rd parties.

Improve usability, reliability, conversion rates and security simultaneously by simply asking the user for permission to access their data on 3rd party services rather than asking for their password.

A single assembly that adds OpenID 1.1/2.0, OAuth 1.0(a)/2.0, & InfoCard authentication and authorization functionality for client and server applications. This allows your (web) application to issue... More information