The convenience of storing things on the cloud can definitely make life easier, but if you're storing sensitive files, it could be a total disaster if anyone hacked your account. Some encryption services can be expensive, but if you just need it for personal use, there are some really great ones that don't cost anything. Here are three programs that let you encrypt your cloud storage for free.
BoxCryptor works with any cloud service and is compatible with Windows, Mac, Android, iOS, and EncFS-Linux. It lets you encrypt individual files instead of whole folders or drives and encrypts everything locally without sending it to any third parties.
You can sign up for a free personal account, which allows you to encrypt one drive, or if you want multiple drives, you can pay the $40 for the unlimited personal account. Even with the free one, though, you can still sync it with as many devices as you want and there's no limit to the storage space.
DataLocker is a program available for Windows, Mac, iPhone and iPad. It lets you store your files locally and on the cloud and it's free and unlimited. Like BoxCryptor, it lets you sync your data across all your devices.
On your computer, you would simply drag and drop the file you want encrypted to the DataLocker application window to encrypt it with a private passphrase. That encrypted file can then be stored anywhere on your local file system or in your Dropbox folder. In order to decrypt the file on another device, that device would also need the DataLocker app. Pretty easy, right?
Cloudfogger is compatible with Dropbox, Google Drive, SkyDrive, and emails, and it works on Windows, Mac (beta), and Android, with iOS support "coming soon."
You can add email addresses to an approved users list to make it easy to share files without giving anyone your password. Cloudfogger also has a Microsoft AddIn that lets you encrypt e-mail attachments on Outlook.
Do you encrypt the data you store in the cloud? Know of any great free encryption programs we missed? Tell us what you use in the comments.