Duplicity

Duplicity is a software suite that provides encrypted, digitally signed, versioned, remote backup of files requiring little of the remote server. Duplicity devises a scheme where the first archive is a complete backup and subsequent backups are only adding differences from the first backup. Chains consisting of a full backup and a series of incremental backups can be recovered to the point in time that any of the incremental steps were taken at. If any of the incremental backups are missing then the incremental backups following it cannot be reconstructed. It does this using GnuPG, librsync, tar, and rdiff. To transmit data to the backup repository it can use SSH/SCP/SFTP, local file access, rsync, FTP, Amazon S3 and Rackspace Cloud Files and others.