If you want to use a security mechanism in your applications, but don't want to be responsible for managing lists of users and passwords, then OpenID may be the answer.
OpenID is an open standard authentication scheme that allows users to log onto many different web sites using the same identity on each of the web sites. There are many different providers of OpenID (for example, Google, Yahoo!, and so on), and also many different web sites that allow users to authenticate using OpenID (http://dzone.com, http://livejournal.com, http://sourceforge.net, and so on). When a user logs on to an OpenID-enabled application, they are redirected to their OpenID provider for authentication. If the user authenticates correctly with their OpenID provider, they are redirected back to the originating application and are automatically authenticated. Using a provider for authentication removes the need for all of the authentication code within a web application, as this is all managed by the OpenID...