I use TrueCrypt to encrypt anything sensitive on my USB drive and I sleep extremely well at night, knowing that no-one in their right mind would try to break its 256-bit AES encryption. While I know that it’s theoretically possible to do so, it doesn’t really matter, because nothing I have is worth dedicating a server farm to brute force it. Some people do have data that important on their USB drives, and that’s why there’s IronKey.
TrueCrypt’s greatest weakness is that it is susceptible to offline attacks. That is to say, if someone gets hold of a TrueCrypt volume, they are able to try a variety of techniques to guess the password, with computer power being their only limitation. TrueCrypt places no limit on how many times you can attempt a password. IronKey, on the other hand, limits you to ten consecutive incorrect attempts. After that, it destroys all the encryption keys and data. For good.
IronKey was developed as a piece of security hardware and, as such, has a bunch of features which make it, to my knowledge, the most hacker-proof data storage device on the market. Not only does it limit the number of incorrect passwords before self-destruct, it also ensures that even the encrypted data cannot be removed from the device, which means it is not susceptible to offline attacks.
First off, you can’t see any data without first authenticating with the device. Second, if you try to physically tamper with the device, the epoxy filling in the device will cause the data and encryption chips to break. Last of all, the device is electron-shielded, so you can’t scan it to elicit data. It’s sturdy metal-cased and epoxy-filled construction keeps your data safe from unintentional physical damage too.
All this, along with hardware-based AES encryption, makes for a very secure device. If you have data that’s worth paying US$79 (for the 1GB version) to protect, take a look. If you’re like me, TrueCrypt is still a phenomenally secure solution.