The problem: Want to buy U.S. military secrets? Try outside the Bagram Air Base in Afghanistan, where thumb drives pilfered from the facility have been sold in open-air markets. Back at home, corporate civilians often use tiny flash devices to shuttle documents between home and office. Losing 4 gigabytes of proprietary data is now as easy as misplacing your car keys.

The solution: Look for USB drives with encryption based on AES - the government's official cryptography algorithm. Kanguru's AES fob costs $50 for 128 megabytes, while Keynesis's Lockngo Professional is a software-based AES implementation that works with conventional USB drives.