OpenID is a decentralized standard that allows users to log into multiple websites using a single digital identity. While OpenID provides convenience, it also introduces security risks such as phishing attacks, man-in-the-middle attacks, replay attacks, cross-site request forgery (CSRF) attacks, and cross-site scripting (XSS) attacks if not implemented securely over HTTPS. Users should be aware of these risks and use caution when using OpenID, especially for sensitive sites like banks.