John the Ripper is a fast password cracker, currently available for many flavors of Unix, Windows, DOS, BeOS, and OpenVMS. Its primary purpose is to detect weak Unix passwords. It supports several crypt(3) password hash types commonly found on Unix systems, as well as Windows LM hashes. On top of this, lots of other hashes and ciphers are added in the community-enhanced version (-jumbo), and some are added in John the Ripper Pro.
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.
Password Manager Daemon serves clients data via a Unix domain socket or over a remote TLS connection. The data is stored in an (optionally) encrypted XML file, and the client must provide the key to modify it. It has the option to use gpg-agent for key management (including smartcards). It is multi-threaded, allowing more than one client to be connected at the same time. Key retrieval may be done via a key file or a pinentry program. A key cache is used, so a client won't need to enter a passphrase each time one is required. It is very configurable. Libpwmd is also available as a separate project and is a library making it easy for applications to use Pwmd.
Lepton's Crack is a generic password cracker. It is easily-customizable with a simple plugin system and allows system administrators to review the quality of the passwords being used on their systems. It can perform a dictionary-based (wordlist) attack as well as a brute force (incremental) password scan, including the use of regular expressions. It supports standard MD4 hash, standard MD5 hash, NT MD4/Unicode, Lotus Domino HTTP password (R4), and SHA-1 hash formats. LM (LAN Manager) plus appending and prepending of characters is available in the Development branch (strongly recommended).
GNU SASL is an implementation of the Simple Authentication and Security Layer framework and a few common SASL mechanisms. SASL is used by network servers such as IMAP and SMTP to request authentication from clients, and in clients to authenticate against servers. The library includes support for the SASL framework (with authentication functions and application data privacy and integrity functions) and at least partial support for the CRAM-MD5, EXTERNAL, GSSAPI, ANONYMOUS, PLAIN, SECURID, DIGEST-MD5, LOGIN, NTLM, and KERBEROS_V5 mechanisms.
ccrypt is a command line utility for encrypting and decrypting files and streams. It was designed as a replacement for the standard Unix crypt utility, which is notorious for using a very weak encryption algorithm. ccrypt is based on the Rijndael cipher, which is the U.S. government's chosen candidate for the Advanced Encryption Standard (AES). This cipher is believed to provide very strong security. A compatibility mode is included for decrypting legacy "unix crypt" files.
Email sends email to remote SMTP servers via the command line, which makes it useful in cron jobs. It will send to any RFC standard remote ESMTP server, is TLS/SSL enabled, and will allow you to encrypt, sign, and design your message on the fly. It has the capability to use signature files with dynamic options, address book functionality, and users can also attach pictures, binary files, documents, or whatever they want. It is completely compatible with GNUPG for encryption and signing, and is easy to configure and use.