Strong support for the open-source operating system within the government came from a surprising quarter in early 2001 with the release of Security-Enhanced Linux from the National Security Agency, which for decades stymied researchers' and technology companies' efforts to create broadly available strong encryption.

SE Linux adds military-strength architecture improvements to Linux, the most obvious security improvement being mandatory access controls, or MACs, based on technology developed by Secure Computing Corp. The Cyberspace Policy Institute plans to also add authentication and key management features to the operating system.

Such technologies make computers much less susceptible to attacks. Mark Westerman, managing partner with network consultant Westcam, installed the SE Linux access controls on a critical server for one of his customers after a common security flaw, known as a buffer overflow, allowed a hacker to take control of the company's server. Westerman configured the access rules but left the buffer overflow unpatched on the server as a test.

When the hacker came back a second time to the server and attempted to gain control of the process, the access controls limited what the attacker could do. Instead of taking control of the computer, the hacker could only crash the service that had the buffer overflow, but do no other damage.

"With the access controls, the customer doesn't have to worry about the next buffer overflow that comes along," said Westerman at a panel discussion at this week's LinuxWorld Conference and Expo. "SE Linux gives you military grade security at open-source cost."