Cryptomator encrypts your files with AES-256 before uploading to iCloud, Google Drive, or Dropbox. Create a vault, set a password, and your data stays private, even if the cloud is breached. Encrypts locally, syncs smoothly on Windows, Mac, Linux, iOS, Android. Super easy, no tech know-how needed. Free, open-source. I use it with Proton Drive, and it syncs as easily as Google Drive or Dropbox.