NOTE: This article was updated 25 June 2018.
Many people are afraid to use Dropbox, Google Drive, or other file storage services because of the fear that “someone might see my personal data.” Whether the fear is valid or not can be discussed forever but there is a simple solution that always avoids the problem: encrypt everything before sending any files to the file storage service. Encrypted files cannot be read by anyone who does not know the encryption key. The result is that your private information remains private.
Of course, you could always manually encrypt the files one at a time by using any of the dozens of available encryption programs. However, if you have hundreds or thousands of files you wish to save online, encrypting them one at a time entails a LOT of work. Luckily, there is a simpler solution and, best of all, it is FREE.
Cryptomator provides transparent, client-side encryption for your files to be stored in the cloud. Cryptomator provides a virtual drive. You can add, edit, or remove files as you’re used to with any other disk drive. Not only do the contents of files get encrypted, even the file names and folder names get encrypted. Only the encrypted files stored in the virtual drive are sent to the file storage service. Cryptomator runs solely in your computer and does not need any infrastructure or accounts under anyone else’s control.
No other person or company has any access to your Cryptomator information. In fact, no one else will even know that you are using Cryptomator unless they have physical access to your computer. Some other file storage services may have access to your encryption keys and therefore may be able to prevent you from accessing your own data, as soon as they decide to change their terms and conditions or shut down completely. This is technically impossible with Cryptomator.
Cryptomator is available for Windows, Macintosh, Linux, Android, and Apple iOS (iPhone, iPad, and iPod touch).. It is free and open source software, so you can rest assured there are no backdoors. Donations are accepted, however. The program will never beg you for a donation.
The biggest drawback I see to Cryptomator is the apps for the iPad, iPhone, and Android devices cost $4.99 each, even though the Windows, macintosh, and Linux versions are available free of charge. Still, $499 is a rather modest price for keeping your secrets private.
The free and open source Cryptomator program is available at: https://cryptomator.org/.