When you're saving sensitive files on your computer meant for your eyes only, make sure you've got the right tools on hand to keep them private. Whether you want to shield your brilliant startup business plan from the Pointy Haired Boss, or hide your stash of Gillian Anderson photos from the kids, there are several free tools that can encrypt, password-protect, or obscure files and folders from others who might use your computer. Let's take a look at various methods, tools, and levels of privacy and security you can use to lock up your sensitive data.
TrueCrypt Encrypts Entire Volumes or Just Folders
The strongest and most bulletproof consumer encryption tool out there is the free, cross-platform, open source TrueCrypt. TrueCrypt requires more setup and elbow grease than other, lesser-secure options, but your efforts buy you Top Secret government file-level security and encryption, the kind that even the FBI agents who break into your house on a surprise sting will have trouble cracking if you manage to close the container before they get to you. (We say this for illustrative purposes, in the hope that you're not reading this to find out how to dodge FBI agents.)
Here's how to encrypt entire disks or subsets of files and folders with TrueCrypt.
Encrypt Passwords (and Files!) with KeePass
To secure a list of passwords or software serial numbers, look no further than KeePass Password Safe, an encrypted database that will lock up your sensitive logins tight as a drum. A lesser-known KeePass feature lets you attach files to database entries, which means you can also use it to lock up data as well (though this works best for files associated with various KeePass entries).
Here's more on how to securely track your passwords (and files) with KeePass.
Hide or Password-Protect Files and Folders with Free Utilities
Several Windows utilities offer ways to assign a password to a folder full of files, or just plain text files. Here's a sampling:
7-Zip: Primarily an archiving, zip utility, the free 7-Zip offers a handy feature for the privacy-minded: the ability to password an archive you create with it. Keep in mind that others can browse file and folder name listings in passworded archives, but the password is required to extract them.
My LockBox (original post): It won't stop someone from finding your files by booting up a Linux live CD, for example, but for a simple way to assign a password to a folder, My LockBox gets the job done.
Free Hide Folder 2.0 (original post): Similar to My Lockbox in that it's low-level protection, Free Hide Folder does a bit more than just checking off the "Hidden" box in Windows' file Properties dialog.
fSekrit (original post): Turn your secret plain text file into a password-protected .exe file with fSekrit, which is small enough to fit snugly on your USB thumb drive.
Mac users, it's very simple for you to create an encrypted disk image with Disk Utility.
Embed Data Inside Innocent-Looking Files with Steganography
If you want to transmit private data via email or embed a password somewhere most people wouldn't dream of looking, you want to try out steganography. A kind of digital invisible ink, stego uses the big mass of bits that make up digital files to obscure private data—so only those with the proper decoder can see it.
Check out our full guide to hiding data in files with easy steganography tools.
Installation-Free Privacy Through Obscurity
If you can't install any special tools on the computer where you'd like to hide files, there are a few low-security Windows tweaks that can help you keep folders out of unwanted hands. You can always hide folders and files inside Windows by checking off that box in the Properties dialog (and making sure that "Show hidden files" isn't enabled in Windows Explorer), but to take things a step further, see how Lifehacker reader Sean uses a blank folder name to hide secret files.
As commenters in the original post point out, this is NOT a high-security tact, it's just enough to keep casual computer browsers from finding your stuff.
What are your favorite methods and tools for hiding private files? Tell us about 'em in the comments.
Gina Trapani, the editor of Lifehacker, likes to keep some folders and files to herself. Her weekly feature, Geek to Live, appears every Monday on Lifehacker. Subscribe to the Geek to Live feed to get new installments in your newsreader.