KeepOut.CN supports the OpenID 2.0 protocol, providing authentication support as an OpenID provider. On request from a third-party site, KeepOut.CN authenticates users who are signing in with an existing KeepOut.CN account, and returns to the third-party site an identifier that the site can use to recognize the user. This identifier is consistent, enabling the third-party site to recognize the user across multiple sessions.

Also the support as OpenID client is available to all registered users, who linked up their own accounts with third-party open identifiers.