Imation Pivot Plus
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Storage Capacity: 1 Gbyte, 2 Gbytes, 4 Gbytes, 8 Gbytes
Casing: Tamper-resistant swivel design with pivot cap
Encryption: Hardware-based 256-bit AES encryption
Special features: Write-protect switch, master password
Speed: Not listed
Price: $70 / $130 / $160 / $260

With the Imation Pivot Plus, the casing stands out as the notable feature. With a pivot cap and a sturdy key ring connector, the product literature claims that "the drive will perform even when exposed to the harshest elements." They probably don't mean iodine, plutonium, and the like, but Imation did expose the Pivot Plus to rapid changes in extreme cold and heat, plus vibration tests. In any event, the device meets U.S. government computer security standards (FIPS 140-2, if you're keeping track) for being tamper-resistant and tamper-evident.

The drive has a single encrypted partition, requiring a password for access. Passwords must be at least seven characters and the device will format itself after seven failed password attempts. For enterprise settings, an administrator can add a master password across a range of Pivot Plus drives.

Storage Capacity: 1 Gbyte, 2 Gbytes, 4 Gbytes
Casing: Durable waterproof (MIL-STD 810F-compliant), tamperproof metal case
Encryption: Hardware-based 256-bit AES encryption
Special features: Self-destruct on tamper, online password storage
Speed: 30-Mbps read, 20-Mbps write
Price: $79 / $109 / $149

The IronKey Enterprise Special Edition was designed for military and enterprise environments. If you tote around a Panasonic Toughbook, this may be the USB drive for you. While the consumer version includes applications to store your Web site passwords and the like, the Enterprise Special Edition sticks to the basics -- authentication and encryption.

With a solid, filled, and waterproof metal casing, it's not only tamper-resistant, but if the on-board "Cryptochip" detects any physical tampering by an adversary, the device will self-destruct, with IronKey's "Flash-Trash" methodology promising an exhaustive erase. Furthermore, the device will wipe clean after 10 incorrect password attempts, and the counter for those attempts is in the hardware -- not the software. This feature defends against a "memory rewind attack," which is among many information security concerns that IronKey addresses in a detailed FAQ.

To counteract the natural tendency to use a Post-It note to store the password for your high-security USB drive, Ironkey also provides a secure password storage service at my.ironkey.com. The drive will also work in conjunction with enterprise device management software.