1.Open standard for authentication,promoted by the non-profit OpenID foundation.
2.As of March 2016,there are over a billion OpenID enabled accounts on the internet and organizations such a Google etc use OpenID to authenticate users
3.A user must obtain an OpenID account through an OpenID identity provider.The user will then use that account to sign into any website (the relying party) that accepts OpenID authentication.
4.OpenID standard provides a framework for the communication that must take place between the identity provider and the relying party.