Duplicati

Duplicati is a free, open source, backup client that securely stores encrypted, incremental, compressed backups on cloud storage services and remote file servers.

The program works with standard protocols like FTP, SSH, WebDAV as well as popular services like Microsoft OneDrive, Amazon Cloud Drive & S3, Google Drive, etc. Duplicati uses strong AES-256 encryption to protect your privacy. You can also use GPG to encrypt your backup.