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.
The stunnel program is designed to work as an SSL encryption wrapper between remote client and local (inetd-startable) or remote server. It can be used to add SSL functionality to commonly used inetd daemons like POP2, POP3, and IMAP servers without any changes in the programs' code. It will negotiate an SSL connection using the OpenSSL or SSLeay libraries. It calls the underlying crypto libraries, so stunnel supports whatever cryptographic algorithms you compiled into your crypto package.
Zorp is a proxy firewall suite with its core architecture is built around today's security demands: it uses application level proxies, is modular and component based, uses a script language to describe policy decisions, makes it possible to monitor encrypted traffic, lets you override client actions, and lets you protect your servers with its built in IDS capabilities.
keychain helps you to manage ssh keys in a convenient and secure manner. It acts as a frontend to ssh-agent and gpg-agent, but allows you to easily have one long running ssh-agent process per system, rather than the norm of one ssh-agent per login session. This dramatically reduces the number of times you need to enter your passphrase. With keychain, you only need to enter a passphrase once every time your local machine is rebooted. keychain also makes it easy for remote cron jobs to securely "hook in" to a long running ssh-agent process, allowing your scripts to take advantage of key-based logins.
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.
ZoneMinder is a suite of applications intended for use in video camera security applications, including theft prevention and child or family member monitoring. It supports capture, analysis, recording, and monitoring of video data coming from one or more video or network cameras attached to a Linux system. It also features a user-friendly Web interface which allows viewing, archival, review, and deletion of images and movies captured by the cameras. The image analysis system is highly configurable, permitting retention of specific events, while eliminating false positives. ZoneMinder supports both directly connected and network cameras and is built around the definition of a set of individual 'zones' of varying sensitivity and functionality for each camera. This allows the elimination of regions which should be ignored or the definition of areas which will alarm if various thresholds are exceeded in conjunction with other zones. All management, control, and other functions are supported through the Web interface.
SecureSkat is a peer-to-peer implementation of the German card game Skat. The program negotiates participating players and game sessions over an arbitrary IRC network (Internet Relay Chat). Neither a trusted third-party (dealer) nor a centralized game server is necessary. All critical operations, e.g. shuffle of the deck, are performed using advanced cryptographic techniques (so-called Mental Poker solutions) provided by LibTMCG. The outdated OpenSkat branch contains a graphical user interface based on XSkat 3.4. This interface can be used with most recent versions, but must be built separately.
Revelation is a full-featured and secure password manager for the GNOME 2 desktop. It aims to be user-friendly and HIG-compliant, and it is tightly integrated with GNOME. It has several account types which can be grouped in folders, searched, and opened in external applications. It can both test and generate passwords. Accounts are stored in an encrypted file which can be accessed remotely via SSH, FTP, HTTP, WebDAV, and more. It can import and export data files for Password Safe, GPass, Figaro's Password Manager, and others.
yaSSL is a C++ based SSL library for embedded and RTOS environments, designed for individuals who prefer to use the C++ language. For a C-based solution, please see CyaSSL. yaSSL supports the industry standards up to TLS 1.2, and also includes an OpenSSL compatibility interface.