CryFS

Cryptomator

Cryptomator is free, open-source software that creates password-protected encrypted 'vaults' on your device, encrypting both file contents and filenames with AES-256 before anything reaches a cloud provider. It works transparently with virtually any cloud storage service, including Dropbox, Google Drive, OneDrive, and iCloud, mounting the vault as a virtual drive so encrypted files behave like a normal folder. Because encryption happens entirely on the local device, the cloud provider only ever stores unreadable ciphertext. The desktop client is free and donation-supported, mobile apps carry a small one-time purchase, and Cryptomator Hub offers GDPR-compliant, centrally managed vault access for small teams.

rclone

rclone is a powerful open‑source command‑line program that lets you sync, copy, and move data between your local filesystem and dozens of cloud storage providers. It runs on Windows, macOS, Linux and can be accessed via web interfaces, making it ideal for developers and power users who need scriptable, automated file operations. With support for encryption, checksums, and bandwidth throttling, rclone provides reliable, high‑performance transfers while giving you full control over authentication and configuration. It is self‑hosted, free, and integrates seamlessly with services like Google Drive, Dropbox, and Amazon S3.

BestCrypt Container Encryption

BestCrypt Container Encryption, made by Finnish security vendor Jetico, creates encrypted virtual containers that behave like normal drives or folders for storing sensitive files. It is built to protect data placed in cloud-sync folders such as Dropbox: because the container is encrypted before it syncs, the underlying cloud provider and anyone who compromises the cloud account only ever sees encrypted bytes. The product works across Windows, macOS, Linux, and Android, and includes a portable BCTraveller tool for accessing encrypted containers on machines without BestCrypt installed. Jetico has built encryption and secure-wiping software for over 30 years and markets BestCrypt alongside its BestCrypt Volume Encryption and data-wiping product lines for endpoint data protection.

Duplicacy

Duplicacy is a cross-platform backup tool from Acrosync LLC that backs up files to a wide range of cloud storage providers, local disks, and SFTP servers. Its core technical differentiator is lock-free deduplication, a chunk-based approach that avoids the centralized locking databases used by many other deduplication backup tools.