File encryption is your best bet if you want to keep The Man, foreign spies, or your annoying roommates out of your files. Here's a look at five of the most popular encryption tools Lifehacker readers use to lock down their files.
GNU Privacy Guard (Windows/Mac/Linux, Free)
GNU Privacy Guard (GnuPG) is an open-source implementation of the the famed Pretty Good Privacy (PGP) encryption tool—you can read the very interesting history of PGP and how GnuPG came to be here. GnuPG is a volume and individual file encryption tool with support for a dozen encryption schemes, paired keys, and expiring signatures. GnuPG doesn't only provide rock-solid local file encryption; it is, thanks to paired encryption and public key servers, a great tool for encrypted communication. Please note, regular old GnuPG is a command line tool. Check out the list of graphical wrappers and application plugins for various operating systems here. The screenshot above is from Cryptophane, a graphical Windows interface for GnuPG.
Disk Utility (Mac, Free)
Disk Utility is a diverse tool that handles almost any disk-related tasks you'd need on OS X. The utility is capable of creating secure disk images and file volumes encrypted with AES 128-bit or 256-bit encryption. Like most native Mac utilities and applications, Disk Utility and the accompanying encryption blends seamlessly into the OS X experience and makes mounting and unmounting encrypted volumes a breeze. If you've never created an encrypted disk using Disk Utility before, take a look at our previous guide.
TrueCrypt (Windows/Mac/Linux, Free)
TrueCrypt is a free, powerful and on-the-fly disk encryption tool. With TrueCrypt, you can create secure encrypted virtual disks or even encrypt entire drives. TrueCrypt is an on-the-fly encryption tool, meaning files are decrypted as you access them and modify them and then encrypted when not in use. Thanks to various optimisation tricks and full utilization of the power of modern processors, working within a TrueCrypt volume feels no different than working on a regular unsecured disk. TrueCrypt not only offers strong and transparent encryption—it also offers the ability to create hidden volumes within encrypted volumes for even more secure (and obscured) file protection.
7-zip (Windows, Free)
Compared to some of the heavyweights in this Hive Five (like GnuPG and TrueCrypt), it might be easy to dismiss the popular file compression tool 7-zip as a lightweight. 7-zip fills a perfect niche for many people, however, by offering simple ZIP container-based encryption. If you're not interested in encrypting a ton of files or maintaining an entire encrypted volume, but you still want to make sure important documents like tax returns are locked up tight, 7-zip sports strong AES-256 encryption. Create a new compressed archive, throw your files in it, and slap a password on. Your files are strongly encrypted and stored right alongside your regular documents.
AxCrypt (Windows, Free)
AxCrypt is a free encryption tool for Windows. Once installed it integrates with the Windows shell and offers simple right-click encryption and decryption of files with AES-256 encryption. Your entire interaction with AxCrypt can take place exclusively from the right-click context menu. In addition to integrating with Windows and offering easy encryption and decryption, you can also use the tool to create self-extracting archives to securely transport files or transfer them to a friend—no AxCrypt installation necessary at the other end.
If you've got experience with any of these tools, let's hear more about what makes it your tool-of-choice in the comments.