The best free open source software for Windows

Satisfy your paranoid streak with TrueCrypt

TrueCrypt is one of those free open source utilities that fly under the radar of most Windows users. Not as flashy or controversial as Microsoft’s BitLocker, TrueCrypt nevertheless provides many of the same features -- full disk encryption with separate key-based recovery -- as well as some that BitLocker does not, like true pre-boot encryption of all volumes. (BitLocker requires that you create a separate, unencrypted pre-boot volume.) In fact, TrueCrypt is superior to BitLocker on many counts, with support for more encryption protocols, more varied encryption scenarios (such as hidden volumes), and more flexibility in how and when you can encrypt your data.

I’m particularly fond of TrueCrypt’s on-the-fly handling of volume encryption. You can start encrypting your disk, pause the process, and resume it later, even after a reboot. And for the truly paranoid among us, TrueCrypt provides the option of creating a second, decoy file system volume that exists in parallel with your actual primary volume. That way, if you’re ever forced to decrypt your volume under duress -- for example, at a security checkpoint or to satisfy the demands of some malfeasant character -- you can enter the decoy password and present them with the bogus volume, leaving them none the wiser.

Of course, TrueCrypt’s hidden decoy volumes and other encryption esoterica are really targeted at niche users with very specific requirements (this means you, 007). However, for the masses, TrueCrypt offers one very compelling feature: It works on virtually any modern NT-based variation of the Windows OS, including Windows 2000 (SP4), Windows XP, Windows Server 2003/2008, and all flavors of Vista (not to mention Mac OS X and Linux).

Bottom line: TrueCrypt’s flexibility, combined with its broad platform support and active development community, make it a terrific free alternative to Microsoft’s BitLocker.