Common Access Card

The Common Access Card, also colloquially referred to as the CAC (often called CAC card, due to what is informally known as RAS syndrome), is a smart card about the size of a credit card. It is the standard identification for active-duty military personnel, Selected Reserve, United States Department of Defense (DoD) civilian employees, and eligible contractor personnel. It is also the principal card used to enable physical access to buildings and controlled spaces, and it provides access to defense computer networks and systems. It also serves as an identification card under the Geneva Conventions (esp. the Third Geneva Convention). The CAC satisfies two-factor authentication: something that belongs to the user, and something only known to the user. And, the CAC covers the bases for digital signature and data encryption technology: authentication, integrity and non-repudiation.

The CAC is a controlled item. As of 2008, DoD has issued over 17 million smart cards. This number includes reissues to accommodate changes in name, rank, or status and to replace lost or stolen cards. As of the same date, approximately 3.5 million unterminated or active CACs are in circulation. DoD has deployed an issuance infrastructure at over 1000 sites in more than 25 countries around the world and is rolling out more than one million card readers and associated middleware.