Duplicati is a free backup client that securely stores encrypted, incremental, and compressed backups on cloud storage services and remote file servers. It supports targets like Amazon S3, Windows Live SkyDrive, Google Docs, Rackspace Cloud Files or WebDAV, SSH, FTP.
Duplicati has built-in AES-256 encryption and backups can be signed using GNU Privacy Guard. A built-in scheduler makes sure that backups are always up-to-date. Last but not least, Duplicati provides various options and tweaks like filters, deletion rules, and transfer and bandwidth options to run backups for specific purposes.