Rekkord

Rekkord is a multi-platform backup tool, with the following features:

Write-only passwords / keys (using asymmetic encryption)
Data deduplication based on content-defined chunking
Data compression with LZ4
Local and remote storage back-ends: local directory, S3 storage, SFTP servers

This software has not been stabilized yet and must not be used as your primary backup tool. You've been warned!

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

Find more information here: https://www.gnu.org/licenses/#AGPL