Classification of information has been widely used in government circles and is increasingly being adapted to protect sensitive data in the private sector. Security clearance of personnel and other controls -- principally encryption -help preserve the security of information from attack of penetration from inside or outside. While they have many unique needs, defense agencies are increasingly using standard, 'off-the-shelf' hardware and software systems. Because of this, the Department of Defense Computer Security Center is encouraging research into computer security, testing commercial products, and approving their use by publishing Evaluated Products Listings. (Publisher abstract)