Cryptomator

Cryptomator is an open-source encryption solution designed to protect files stored in cloud services such as Dropbox, Google Drive, OneDrive, and others. It creates secure, encrypted “vaults” on your local device, ensuring that data is encrypted before it is synchronized to the cloud. The primary purpose of Cryptomator is to provide transparent, client-side encryption so that only you control access to your files, regardless of the cloud provider’s security model.

The tool uses strong, audited cryptographic standards (including AES encryption) and operates with a zero-knowledge approach, meaning no passwords or keys are ever shared with third parties. Cryptomator works via virtual drives: you access and edit files in a familiar folder structure while the software handles on-the-fly encryption and decryption. It encrypts both file contents and filenames, and supports multiple vaults for different projects or accounts. Being open source, its codebase is publicly inspectable, which enhances transparency and allows independent security reviews.