Cloud storage can be a tempting offsite backup approach, but without some sort of encryption one runs the risk of accidentally publishing all the files they've backed up to the world. Cryptomator provides such an encryption layer. It provides a virtual hard drive that users can treat like a USB stick. But under the covers, Cryptomator transparently uses industry standard AES encryption to encode your files before storing them on a cloud provider. The encryption key used is generated from a user-specified password using the standard scrypt algorithm; there is no additional key or account management beyond that. Cryptomator is licensed under the GPLv3, with full source code available on github. Desktop versions of Cryptomator are available for Windows, macOS, and Linux. Mobile versions are available for iOS and Android.