TrueCrypt is a free, open source encryption application that works on Windows and Linux. Given the right credentials, TrueCrypt will create a virtual hard drive that will read and write encrypted files on the fly.
Just Do It!
- Download TrueCrypt, install and launch.
- Hit the Create Volume button to launch the wizard that prepares the encrypted drive location. Choose Create a Standard TrueCrypt Volume and hit Next. Hit the Select File button and navigate to a location to store your encrypted files and type a name for it. There are a few good suggestions when using TrueCrypt with Dropbox here. Keep in mind that this isn’t the file you want to encrypt; it’s a big file container that will store the files you want encrypted all scrambled up like eggs inside it. Hit Next.
- Choose your encryption algorithm. The curious can flip through the dropdown and view info on each option, but you pretty much can’t go wrong here; the default AES selection will work for most purposes. (Hey, if it works for Top Secret government files, it probably will work for you.) Hit Next.
- Choose the size of the virtual drive – for example, 100MB. (Or if you’re encrypting your Dropbox account, you know your maximum is 16GB)Yes, it’s a pain to have to commit to a size beforehand, but the advantage here is that the file will always look like it’s exactly 100MB, giving no hint to the actual size of its contents. Hit Next.
- Choose your volume password. TrueCrypt wants something totally insane, like 20 characters with letters and numbers mixed together, something hard to crack. The whole point here is to keep snoopers at bay, so make your password reasonably difficult to crack or guess.
- Format the volume. This part is cool: TrueCrypt gathers random information from your system – including the location of your mouse pointer – to format the file drive location with random data to make it impossible to read. Hit the Format button to go ahead with this operation, which may slow down your computer for a few seconds. (And don’t be scared by the word “Format”; you’re not erasing your hard drives or anything, you’re just formatting the drive location file you just created.)
Congrats! Your encrypted volume location is ready for use.