Unix security software

Enigmail is a data encryption and decryption extension for Mozilla Thunderbird and the Postbox that provides OpenPGP public key e-mail encryption and signing. Enigmail works under Microsoft Windows, Unix-like, and Mac OS X operating systems. Enigmail can operate with other mail clients compatible with PGP/MIME and inline PGP such as: Microsoft Outlook with Gpg4win package installed, Gnome Evolution, KMail, Claws Mail, Gnus, Mutt. Its cryptographic functionality is handled by GNU Privacy Guard.

p0f is a passive TCP/IP stack fingerprinting tool. p0f can attempt to identify the system running on machines that send network traffic to the box it is running on, or to a machine that shares a medium with the machine it is running on. p0f can also assist in analysing other aspects of the remote system.

free software