The United States Air Force is piloting a card authentication system to validate Department of Defense (DoD) employees.
Employees will use the Common Access Cards (CACs) as authentication tokens.
The first phase of the PKI project will enable users to digitaly sign emails.
The Air Force is using messaging firm Tumbleweed's Valicert Validation Authority solution.
A spokesman for the company said, "These smart cards offer a great deal of security to normal activities, such as adding identity, confidentiality to email messages, and permitting entry into computer networks."