Duplicity incrementally backs up files and directory by encrypting tar-format volumes with GnuPG and uploading them to a remote file server. In theory many protocols for connecting to a file server could be supported; so far ssh/scp, local file access, rsync, ftp, HSI, WebDAV and Amazon S3 have been written. Because duplicity uses librsync, the incremental archives are space efficient and only record the parts of files that have changed since the last backup. Currently duplicity supports deleted files, full unix permissions, directories, symbolic links, fifos, device files, but not hard links.