The Open ID scheme is a distributed digital identity system that enables Internet users to use single identity repository to store account information for every site they log in.

Open ID can be even used for authenticating banking and e-commerce transactions, provided strong authentication method is enabled.

The idea of Open ID has won the support of Microsoft that intend to share parts of its technology with Open ID developers. The outcome of this cooperation has to be a reduced number of passwords Microsoft's users will be forced to memorise.

But some sites such as online banks show demand far more secure authentication methods than those required for example by blog sites. Open ID aims to remove this problem by authenticating users with web addresses they provide instead of a username and password. In the background an automated Open ID mechanism checks and verifies the site supplied.

Microsoft has got involved to development of InfoCards to add more flexibility for the Open ID users. The InfoCard program allows Internet users to identify themselves by supplying varying degrees of information depending on who is asking them to authenticate.