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.
Keep in Touch aims to be a secure IM system for multiple platforms. It supports its own XML-based protocol as well as ICQ and AIM (toc). It provides encrypted connections between the server and client aswell as encrypted chat on all supported networks. The client can store contacts on the server allowing users to keep their contact lists between different locations.
KOSd is a modified version of Ascend's RADIUS (derived from Livingston's) daemon that supports GECOS password files in another location than /etc/passwd. The path to the file is configurable in a C file. It's great for segmenting dial-in and email-only users on a dialing pool, supporting both Max units and Xylogics (now Bay) servers from a single password file, and probably others. It will probably work with Cisco or Livingston servers as well by changing the dictionary file and turning off the -DASCEND extensions within the makefile, but you may need to experiment. This product is totally unsupported.
The Legion of the Bouncy Castle Java Cryptography API provides a lightweight cryptography API in Java, a provider for the JCE and JCA, a clean-room implementation of the JCE 1.2.1, generators for Version 1 and Version 3 X.509 certificates, generators for Version 2 X.509 attribute certificates, PKCS12 support, and APIs for dealing with S/MIME, CMS, OCSP, TSP, CMP, CRMF, EAC, DVCS, OpenPGP, DTLS, and TLS. Versions are provided for the J2ME, and JDK 1.0-1.7.
Libmcrypt is a library which provides a uniform interface to several symmetric encryption algorithms. It is intended to have a simple interface to access encryption algorithms in ofb, cbc, cfb, and ecb modes. The algorithms it supports are DES, 3DES, RIJNDAEL, Twofish, IDEA, GOST, CAST-256, ARCFOUR, SERPENT, SAFER+, and more. The algorithms and modes are also modular so you can add and remove them on the fly without recompiling the library.
Libnids is a library that provides the functionality of one of the NIDS (Network Intrusion Detection System) components, namely E-component. Libnids code watches all local network traffic, cooks received datagrams a bit, and provides convenient information about them to the NIDS analyzing modules. Libnids performs assembly of TCP segments into TCP streams, IP defragmentation, and TCP port scan detection.
Libslack is a library of general utilities designed to make UNIX/C programming a bit easier on the eye. It was originally implemented as part of the daemon program. It's a small library with lots of functionality, is accurately documented and was thoroughly tested. Good library naming conventions are not rigorously observed on the principle that common operations should always be easy to write and code should always be easy to read.