CryFS

CryFS encrypts your files locally so you can safely store them in cloud services like Dropbox, iCloud, or OneDrive. Unlike tools that encrypt files one by one, it also hides file sizes, directory structure, and metadata, so a cloud provider sees only opaque blocks instead of your folder layout.

It runs as a FUSE filesystem you mount from the command line: point it at an encrypted storage folder and a mount point, enter a password, and work with your files normally while everything is encrypted at rest. CryFS supports the XChaCha20-Poly1305 and AES-256-GCM ciphers and lets you tune scrypt parameters when creating a filesystem to balance speed against brute-force resistance.

SiriKali and Plasma Vault provide graphical front ends for those who prefer not to use the terminal.