Software giant Microsoft has come up with the most secure distribution version of Windows XP ever. The downside is that you can't have it.

The US Air Force persuaded the delightfully understated Microsoft CEO Steve Ballmer to provide it with a secure Windows configuration that would save the service about $100 million in contract costs and countless hours of maintenance. It has more than 600 settings which are locked down tight, and critical security patches can be installed in an average of 72 hours instead of 57 days.

The work is the result of an NSA conducted penetration tests on the Air Force network which found that more than two-thirds of their intrusions were possible because of poorly configured software that created vulnerabilities. Some operating systems came bloated with unsecured features that were never re-configured securely by Air Force administrators. Some systems that were configured securely became vulnerable later after a re-install.

Apparently Microsoft quickly agreed to the plan to create a secure Windows out of the box and Ballmer got personally involved in the project. One change was how XP handled passwords so that administrative passwords were unique, and different from general user passwords. Passwords had to be longer and expired every 60 days.

It then took two years for the Air Force to catalog and test all the software applications on its networks against the new configuration to uncover conflicts. Microsoft installed automated tools to update patches and to detect and prevent someone from altering the configuration.