Daemon implementing IDENT protocol, it can be used to identify the user who initiated a TCP/IP connection

OpenPGP (RFC2440) implementation from the GNU project. Encrypts/decrypts/signs/digests files using strong cryptography. FAQ, downloads, documentation.

lsof is a tool for examining I/O channels open on your Unix system. These can include files, FIFOs and network sockets. This information can be extremely useful for security and a variety of other purposes. Works on most Unix-like systems.

A replacement for the Unix crypt, using several block algorithms in several modes like cbc, and cfb.

The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, fully featured, and Open Source toolkit implementing the Secure Sockets Layer and Transport Layer Security protocols with full-strength cryptography world-wide.

Run selected commands as root, with the users' own password. Allows the administrator to grant limited root privileges to a subset of users, without giving out the root password.

(Security Administrator's Integrated Network Tool) Scans systems and networks and reports potential vulnerabilities.

Tools such as tcpdump and traceroute.

Efficient stealth port scanner. Downloads, e-mail lists, news.

Strong cryptographic software, libraries, and information about cryptography, data security, and privacy.