Dar is a shell command that makes backup of a directory tree and files. Its features include splitting archives over several files, DVD, CD, ZIP, or floppies, compression, full or differential backups, strong encryption, proper saving and restoration of hard links, extended attributes, file forks, Door inodes, and sparse files, remote backup using pipes and external commands (such as ssh), and rearrangement of the "slices" of an existing archive. It can run commands between slices, before and after saving some defined files or directories (for a proper database backup, for example), and quickly retrieve individual files from differential and full backups. Several external GUIs exist as alternatives to its CLI interface, like kdar, DarGUI, SaraB, etc.
The MD5 message digest library implements the MD5 message digest algorithm specified in RFC 1321 directly from the specification, without copying from the reference implementation and therefore without requiring mention of RSA when used. It uses the same unrestricted-distribution license as zlib.
PGP (Pretty Good Privacy) is a public key encryption program originally written by Phil Zimmermann in 1991. Later PGP versions have been developed and distributed by MIT, ViaCrypt, PGP Inc., and now Network Associates Inc. (NAI). PGP is the de-facto standard for email encryption today, with millions of users worldwide.
The RAZip bitstream format was designed to provide a faster random access to compressed data than what is currently possible using the GZIP format. Its major features include fast random access to compressed data, freedom from patents, single-pass coding/decoding using a bounded amount of intermediate storage, the ability to choose from one of many algorithms for compression, encryption, or error correction, and comprehensive support for Unix file metadata, Macintosh file metadata, and arbitrary file metadata.