A quick look at In Win's Ammo encrypted hard drive enclosure


128-bit AES encryption with a side of RFID
— 9:23 AM on August 25, 2009

If you need to carry a lot of data around, it's hard to beat the utility and value wrapped up in an external 2.5" hard drive enclosure. They're are cheap, and considering that 500GB mobile drives can be had for under $90, you'd be hard pressed to find a similarly portable solution with a lower cost per gigabyte. Plus, in true enthusiast spirit, you can buy the enclosure and hard drive separately and put them together yourself.

Desktop hard drives may have reached 2TB, but half a terabyte is still incredible amount of storage capacity these days. That's plenty of room for all sorts of things, such as backups of personal and work files, loads of digital pictures, and that vast multimedia library Linux ISO collection you've been liberating from BitTorrent—stuff you wouldn't necessarily want falling into the wrong hands should your external drive be lost, stolen, or otherwise left unattended.

The easiest way to shield your data from prying eyes would be to the encrypt the contents of your portable hard drive. Recent versions of Windows have encryption measures built-in, and you can also opt for free third-party applications like TrueCrypt. There is a catch, though. Without a dedicated ASIC to handle the number crunching, encryption software tends to be rather demanding of CPU cycles. Encrypting or decrypting multiple gigabytes takes time, even on modern PCs.

So, why not put an encryption ASIC into an external enclosure? That's what In Win has done with the Ammo, a 2.5" USB hard drive caddy protected by 128-bit AES encryption.


128-bit encryption is hardly fit for the Pentagon, but In Win has gone with a military theme anyway. The Ammo's casing is modeled after a magazine that, based on years of semi-accurate firearms portrayal in first-person shooters, looks to me like a particularly high-capacity clip for a .50 caliber sniper rifle. Awesome. Plus, the steel shell has a matte black finish that's subtly sinister. Thank you, In Win, for not tarting up the unit with a gaudy urban-camo motif.

While I like the Ammo's chunky styling, the casing is a little portly. The Ammo measures 143 x 86 x 21 mm (5.6" x 3.4" x 0.8"), which is wider, thicker, and longer than every other mobile drive enclosure I have kicking around the Benchmarking Sweatshop. But then the Ammo also has considerably more padding under the hood.


Sliding off the Ammo's outer casing reveals a rubber-like sled ready to accept a 2.5" Serial ATA drive. There are no screws to secure a drive in place; instead, you simply stretch the sled around it. The fit is surprisingly snug and secure, and along with some added shock protection, the sled should provide a measure of noise and vibration dampening. Mobile hard drives don't produce much of either, though.

In the picture above, you can also see the Ammo's circuit board, which hosts the Innmax IM7206 silicon that runs the entire show. The Innmax chip consolidates a USB-to-SATA bridge, 128-bit AES encryption/decryption engine, and an RF decoder all under one roof. So what's the RF decoder for?

Rather than gating access to a drive's contents with a password, fingerprint scanner, or old-school combination lock, the Ammo comes with two RFID keys that can be used to lock and unlock the drive. One of these keys is a faux dog tag that fits the Ammo's theme perfectly, but isn't something most folks would want to wear. Fortunately, the other key is a discrete little bit of red plastic that'll easily fit on a keychain.


Before firing up the Ammo for the first time, one has to authenticate the included RFID keys. Fortunately, this process takes only seconds: hold the keys next to the designated spot on the enclosure, wait for the appropriate beep code, and you're done. The Ammo is designed to work only with its bundled RFID tags, so you can't substitute the government implant being used to monitor your every move. Sorry.

When locked, the Ammo presents itself to Windows as an RFID device without even a hint that there's a hard drive inside. Only when you swipe one of the keys to unlock the drive is the Ammo recognized as a standard external storage device.

Masquerading as an RFID device when locked will probably make the Ammo confusing enough to casual thieves to deter further meddling. However, if someone were enterprising enough to remove an encrypted hard drive from the Ammo and hook it up directly to a PC, either via a SATA port or another enclosure, all they'd see is an uninitialized disk, free of partitions. It's possible to initialized and re-partition an otherwise encrypted drive to make it usable, but you can't get at any of the encrypted data previously written to the disk. Heck, there's really no indication that the drive had anything on it to begin with.

Unlike with software-based encryption schemes, there's no delay associated with locking or unlocking the Ammo. In fact, the process was instantaneous no matter how much data was on the 160GB drive I used when testing the enclosure. More importantly, locking and unlocking really couldn't be simpler. There are no passwords to remember, no software to install, and nothing else that might otherwise confuse your mother. An LED on the magazine even switches between red and green to indicate whether the drive is in a locked state.

Encryption doesn't slow the Ammo's transfer rates, either. With an unpartitioned drive inside the magazine, HD Tach measured sustained read and write speeds of 33 and 31MB/s, respectively. Those transfer rates held up with real-world file transfers to and from the drive, as well. 33MB/s still isn't all that quick, relatively speaking, but it's as good as we've seen from an external USB storage device.


In Win rounds out the Ammo with a two-pronged USB cable and the screwdriver you'll need to pull the magazine apart. Most 2.5" hard drives should have little problem running with only one USB port providing power, but if you're going to use a 7,200-RPM drive, the second plug may be required. Of course, there's no need to use a high-performance drive with the Ammo; its transfer rates will be limited by the USB interface long before a 5,400-RPM spindle speed becomes the limiting factor.

Online vendors are selling the Ammo for $33, which is a little pricey for a 2.5" enclosure. But then the Ammo is more than just a hard drive case with a USB interface. This is the perfect USB enclosure for Ted Nugent types: it'll look right at home on a bandolier, and encryption will keep the government all out of your data.

Unfortunately, the military theme may also be the Ammo's greatest liability. The rugged styling will surely turn off some folks, even if it's just to avoid potential hassles with airport security. The fact that the Ammo is twice the thickness of typical 2.5" enclosures is also a concern.

If you don't mind the bulk, the Ammo is easy to recommend for personal storage, off-site backups, or really anything else you might do with an external hard drive enclosure. Let's hope In Win brings this encryption technology to slimmer enclosures with more conservative styling, as well.TR

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