Compressing, deduplicating backup tool.
Offsite backups require SFTP. Data is encrypted and authenticated on the client unless explicitly disabled. Prefer encryption modes that use BLAKE2 for authentication, such as repokey-blake2.
Disclaimer: Using the recommended projects on this site will not guarantee that 100% of your communications will be shielded against surveillance states. Please do your own research before trusting these softwares with sensitive information.