Version 5 of Encrypt Stick remains one of the most secure and least intrusive ways to store and encrypt sensitive data. It installs to and runs off of your USB thumb drive, and leaving no footprint on your (or others') PC or Mac. It also uses polymorphic encryption (the algorithm will change for each device it runs from) that the company claims is 10 times faster than 256-bit AES, and provides a virtual keyboard to prevent key-logging programs from stealing your password. Encrypt Stick is available in a full $40 version and a Free version, which is basically a demo of the full version.
ENC Security Systems has addressed every minor complaint I had about the previous version. It's now readily apparent that the program runs from your flash drive, and the interface is nigh-on flawless. Aside from fixes, version 5 of the paid version adds a secure Web browser that launches from within the Encrypt Stick interface. The browser rendered the limited number of sites I visited just fine, but trying to watch videos on YouTube was a frustrating, stuttering experience. But YouTube is not what you use a secure browser for anyway. You use Encrypt Stick's browser to prevent malware attacks, and it does this nicely by preventing third-parties from installing any kind of software, including plug-ins.
My only issue with Encrypt Stick is the same one I have with all software-based encryption--speed, or lack thereof compared to a hardware-based secure drive. That's more than made up for by the cost differential. You may use Encrypt Stick on as many drives as you want while hardware-encrypted flash drives are expensive.
The free version of Encrypt Stick is limited to 20MB of storage and one group of passwords, etc.--and it restricts use of the Web browser to 30 days--but it's still quite useful. A detailed feature comparison with the $40 full version can be found on the company's Web site. All-in-all, Encrypt Stick is a most worthy program and much improved since my last look. Highly recommended if you need to secure your data on a flash drive.