About Common Access Card

A Common Access Card (CAC) is a United States Department of Defense (DoD) smart card used by military personnel and other government and non-government personnel who require highly secure access over the Internet. A CAC uses PKI authentication and encryption.

Using a CAC requires an external card reader connected on a USB port.

The Client Certificate Check was developed for use with a CAC; however, it is useful in any scenario that requires a client certificate on an HTTPS/SSL connection. CAC support is available for client certification only on HTTPS connections.

CACs might not work with browsers other than Microsoft Internet Explorer.