OpenID

OpenID is an open standard that describes how users can be authenticated in a decentralized manner, eliminating the need for services to provide their own ad hoc systems...

Free Open Source Web

OAuth

OAuth is an open standard for authorization. It allows users to share their private resources (e.g. photos, videos, contact lists) stored on one site with another site...

Free Open Source Web

Portier

Portier (pronounced "Por-tee-ay") is a self-hostable login service that you can use instead of passwords. Portier sits between your website and third-party...

Free Open Source Web Self-Hosted

Twitter connect

Place a button on your site or application which allows Twitter users to enjoy the benefits of a registered user account in as little as one click. Works on websites...

Free Web

Persona

Persona (formerly BrowserID) allows you to sign in to sites using an email address you choose. So, instead of having to manage multiple usernames and passwords across...

• Discontinued
  Notice on official site: "Persona is no longer actively developed by Mozilla. Mozilla has committed to operational and security support of the persona.org services until November 30th, 2016. On November 30th, 2016, Mozilla will shut down the persona.org services. Persona.org and related domains will be taken offline." See https://developer.mozilla.org/en-US/Persona

Free Open Source Web

EMCSSL

Distributed network security infrastructure based on self-signed clients SSL certificates and cryptocurrency blockchain Full description here:...

Free Open Source Mac Windows Linux

IndieAuth

IndieAuth is a way to use your own domain name to sign in to websites. It works by linking your website to authentication providers such as Twitter or Google, then...

Free Open Source Web Self-Hosted

Facebook Connect

Facebook Connect is a set of APIs from Facebook that enable Facebook members to log onto third-party websites, applications, mobile devices and gaming systems with their...

Free Web