BeeCrypt is an ongoing project to provide strong and fast cryptography in the form of a toolkit usable by commercial and open source projects. Included in the library are entropy sources, random generators, block ciphers, hash functions, message authentication codes, multiprecision integer routines, and public key primitives.
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 Openwall Linux kernel patch is a collection of security "hardening" features for the Linux kernel. In addition to the new features, some versions of the patch contain various security fixes. The "hardening" features of the patch, while not a complete method of protection, provide an extra layer of security against the easier ways to exploit certain classes of vulnerabilities and/or reduce the impact of those vulnerabilities. The patch can also add a little bit more privacy to the system by restricting access to parts of /proc so that users may not see what others are doing.
vpnd is a daemon which connects two networks on network level either via TCP/IP or a (virtual) leased line attached to a serial interface. All data transfered between the two networks are encrypted using the unpatented free Blowfish encryption algorithm with a key length of up to 576 bits (may be downgraded to a minimum of 0 bits to suit any legal restrictions).
ImSafe (Immune Security For your Enterprise) is a host-based intrusion detection tool. After a learning phase, it is able to detect changes in processes behavior, to detect buffer overflows, etc. It is implemented through a device driver (as a kernel patch) for the Linux kernel, but can also be run on other UNIX systems by using a "sensor" built upon strace.
Botan is a crypto library written in C++. It provides a variety of cryptographic algorithms, including common ones such as AES, MD5, SHA, HMAC, RSA, Diffie-Hellman, DSA, and ECDSA, as well as many others that are more obscure or specialized. It also offers SSL/TLS (client and server), X.509v3 certificates and CRLs, and PKCS #10 certificate requests. A message processing system that uses a filter/pipeline metaphor allows for many common cryptographic tasks to be completed with just a few lines of code. Assembly and SIMD optimizations for common CPUs offers speedups for critical algorithms like AES and SHA-1.
Owl (Openwall GNU/*/Linux) is a small security-enhanced Linux distribution for servers. Owl also makes a good base system for customized virtual machine images and embedded systems, and Owl live CDs with remote SSH access are good for recovering or installing systems (whether with Owl or not). A single Owl CD includes the full live system, installable packages, the installer program, as well as full source code and the build environment capable of rebuilding the entire system from source. Owl supports multiple architectures (x86, x86-64, SPARC, and Alpha) and offers some compatibility for packages developed for other Linux distributions. The primary approaches to security are proactive source code review, privilege reduction, privilege separation, careful selection of third-party software, safe defaults, and "hardening" to reduce the likelihood of successful exploitation of security flaws.
SOSSE (Simple Operating System for Smartcard Education) is a free smart card operating system. It is implemented in C and assembler for the Atmel AVR smart cards (Funcard, PinkCard, Jupiter). The aim of this project is to provide something like Linux for smart cards, which is a market full of NDAs. SOSSE should make it possible to learn about smart cards, and to implement and test your own ideas.
Libecc is a C++ elliptic curve cryptography library that supports fixed-size keys for maximum speed. The goal of this project is to become the first free Open Source library providing the means to generate safe elliptic curves, and to provide an important source of information for anyone with general interest in ECC.
Fenris is a multipurpose tracer, debugger, and code analysis tool that detects and documents high-level language constructions, can recover symbols, graph program execution flow, detect internal functions, recover symbol tables, and deal with anti-debugging protection. It features a command-line interface as well as a SoftICE-alike GUI and Web frontend.