Cryptomator is described as 'Provides transparent, client-side encryption for your cloud. Protect your documents from unauthorized access. Cryptomator is free and open source software, so you can rest assured there are no backdoors' and is a very popular file encryption software in the security & privacy category. There are more than 50 alternatives to Cryptomator for a variety of platforms, including Windows, Mac, Linux, Android and iPhone apps. The best Cryptomator alternative is VeraCrypt, which is both free and Open Source. Other great apps like Cryptomator are Rclone, TrueCrypt, Picocrypt and Tresorit.