samhain is a daemon that can check file integrity, search the file tree for SUID files, and detect kernel module rootkits (Linux only). It can be used either standalone or as a client/server system for centralized monitoring, with strong (192-bit AES) encryption for client/server connections and the option to store databases and configuration files on the server. For tamper resistance, it supports signed database/configuration files and signed reports/audit logs. It has been tested on Linux, FreeBSD, Solaris, AIX, HP-UX, and Unixware.
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.
Site Change Detection is a class that scans a directory to detect file changes. It performs an initial scan of a given directory and records the names and hashes of files found in a MySQL database. Subsequent scans detect any files that were added, changed, or deleted. The class can also setup the database tables to perform the initial configuration.
GnuTLS is a secure communications library implementing the SSL, TLS, and DTLS protocols and technologies around them. It provides a simple C language application programming interface (API) to access the secure communications protocols, as well as APIs to parse and write X.509, PKCS #12, OpenPGP, and other required structures. It is intended to be portable and efficient with a focus on security and interoperability.
Endian Firewall is an all-in-on Linux security distribution that turns any system into a full-featured security appliance. It features a stateful packet inspection firewall, application-level proxies for various protocols (HTTP, POP3, SMTP), anti-virus support, virus and spam filtering for email traffic (POP and SMTP), content filtering of Web traffic, and a "hassle free" VPN system based on OpenVPN.