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.
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.
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).
crypt_blowfish is an efficient implementation of a modern password hashing algorithm, based on the Blowfish block cipher, provided via the crypt(3) and a reentrant interface. It is compatible with bcrypt as used in OpenBSD. It is adaptable to future processor performance improvements, allowing you to arbitrarily increase the processing cost of checking a password while still maintaining compatibility with your older password hashes. The hashes it produces are several orders of magnitude stronger than traditional Unix DES-based or FreeBSD-style MD5-based hashes.
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.
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.
HAVEGE (HArdware Volatile Entropy Gathering and Expansion) is a user-level software unpredictable random number generator for general-purpose computers that exploits modifications of the internal volatile hardware states as a source of uncertainty. It combines on-the-fly hardware volatile entropy gathering with pseudo-random number generation. The internal state includes thousands of internal volatile hardware states and is merely unmonitorable. It can support several hundreds of megabits per second on current workstations and PCs.
The ELF-Encrypter program suite is a collection of programs to encrypt ELF binaries using various algorithms, including the ones provided by GPG. One can choose a lot of methods to obtain the encryption key, such as hashing a list of PCI peripheals, MAC addresses of ethernet cards, file inode numbers, passphrases and passwords. The suite also contains programs to manipulate and inject plain or encrypted code into ELF binaries.
Unicornscan is an information gathering and correlation engine. It was designed to provide an engine that is scalable, accurate, flexible, and efficient. Unicornscan is an attempt at a user-land distributed TCP/IP stack. It is intended to provide a researcher with a superior interface for introducing a stimulus into and measuring a response from a TCP/IP enabled device or network.
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.