When comparing duplicity vs Tarsnap, the Slant community recommends duplicity for most people. In the question“What are the best backup programs for Linux?” duplicity is ranked 2nd while Tarsnap is ranked 9th. The most important reason people chose duplicity is:
Data is encrypted locally before being sent, and kept encrypted by a key that is never stored on the remote machine. So you might even store your data on a public space, people would still need your key or brute force it.
Specs
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Pros
Pro Encrypted locally before sending (using GnuPG)
Data is encrypted locally before being sent, and kept encrypted by a key that is never stored on the remote machine. So you might even store your data on a public space, people would still need your key or brute force it.
Pro Bandwidth and space efficient
Duplicity uses the rsync algorithm so only the changed parts of files are sent to the archive when doing an incremental backup. For instance, if a long log file increases by just a few lines of text, a small diff will be sent to and saved in the archive. Other backup programs may save a complete copy of the file.
Pro Versioning and incremental backup
You can retrieve older versions or files you recently deleted locally even after having updated your backup.
Pro Free and open-source
Licensed under GNU GPL v2.
Pro Works with scp/ssh, ftp, rsync, Amazon S3...
Duplicity does not make many demands on its archive server. As long as files can be saved to, read from, listed, and deleted from a location, that location can be used as a duplicity backend. Besides increasing choice for the user, it can make a server more secure, as clients only require minimal access.
Pro Has a Dockerized image
Docker allows to run programs on any Linux without having to really install them, and allows to manage versions so it runs exactly the same on different machines.
Pro Focus on encryption and deduplication
Encryption allows the use to access their files with only their own keys and the deduplication saves on costs of storage as any duplicate file will be removed automatically. So not only is the platform safety minded but cost is taken into account for the user as well.
Pro No need to worry about versioning
Cons
Con You have to invest a few minutes in setup time
Con No automatic deletion of old backups
Users will have to manually delete their old backups as there is no way to set a threshold of when older backups should be removed.