The U.S. Army’s Common Access Card (CAC) Guide

The Common Access Card (CAC) is more than just an identification card for the U.S. Army; it’s an essential tool for security, access, and digital functions for members of the Department of Defense (DoD). This guide will walk you through its purpose, its authorized users, and how to use it, especially in the context of computer operations.

Who is Authorized to use the CAC?

The CAC is not exclusively for the Army; it is used throughout the Department of Defense (DoD). Authorized users include:

Active Duty Military Personnel: This includes all branches of the military, not just the Army.

Reserve Military Personnel: Members of the Reserves for all military branches.

DoD Civilian Employees: Non-military personnel who are employed by the DoD.

Contractors: Individuals from private sector companies who are under contract to the DoD. They must be sponsored by a DoD government agency or military department.

Other Non-DoD Government Employees: In certain cases, government employees from other federal agencies may be issued a CAC when working on DoD assignments.

How to Use the CAC?

At its core, the CAC serves as an identification card, but its embedded technology offers various other functionalities:

Physical Access: The CAC can be used to gain access to controlled areas on military and DoD installations.

Logical Access: When combined with a personal identification number (PIN), the CAC gives users access to DoD computer networks and systems.

Encryption and Digital Signatures: The CAC can be used to encrypt emails, ensuring that only the intended recipient can read them. It can also be used to digitally sign documents and emails, providing verification of the sender’s identity and the integrity of the message.

How to Install CAC Certificates on a PC

To utilize the full functionality of the CAC with a personal computer, the machine must recognize the card and its certificates. Here’s a step-by-step guide on how to do this:

Acquire a CAC Reader: Before you can use your CAC with your PC, you’ll need a compatible CAC reader. These are available at many military exchanges or online. Plug the CAC reader into a USB port on your computer.
Install the Necessary Software: Depending on the operating system of your PC, you might need specific middleware software to bridge communication between the computer and the CAC.
Download and Install DoD Certificates:

Go to the DoD PKI (Public Key Infrastructure) website. This is the central repository for all DoD certificates.
Locate the section for ‘Trust Store’ or ‘Certificates.’
Download the necessary certificates for your operating system. This typically includes root and intermediate certificates.
Install the certificates on your PC. The exact process will vary depending on your operating system.

Test the Installation: Insert your CAC into the reader and try accessing a CAC-enabled DoD website. If prompted, select the appropriate certificate and enter your PIN.

Where to Download DoD Certificates?

As mentioned above, to use your CAC with a computer, you’ll need to install the appropriate DoD certificates. These certificates tell your computer to trust the card and its contents.

To obtain the DoD certificates:

Navigate to the official DoD PKI website. Ensure you are visiting the legitimate DoD site to prevent downloading malicious or fraudulent certificates.
Look for sections labeled ‘Trust Store,’ ‘Certificates,’ or similar. The exact naming may vary.
Download the necessary certificates. Depending on your needs and the purpose, there might be different sets of certificates to download, including root, email, and intermediate certificates.
Install the certificates on your PC.

The Common Access Card is an integral part of the U.S. Army’s and the wider DoD’s operations. It provides a robust system for identity verification, secure communication, and access control. By understanding its functionalities and knowing how to properly set it up on personal computers, CAC holders can ensure they are taking full advantage of this valuable tool. Remember always to keep your CAC safe and report any loss immediately to prevent unauthorized use.