Multi-platform Security Tools

Sorted alphabetically by name

Kismet

Kismet is an 802.11 layer 2 wireless network detector, sniffer, and intrusion detection system. Kismet will work with any wireless card which supports raw monitoring (rfmon) mode, and can sniff 802.11a, 802.11b, and 802.11g traffic.

PuTTY

PuTTY is a free implementation of Telnet and SSH for Windows and Unix platforms, along with an xterm terminal emulator.

TrueCrypt

TrueCrypt creates virtual encrypted file-systems which can be stored as a file or as a whole disk partition. Works on USB sticks too. Don't lose your data if your PC is stolen -- encrypt it!

WireShark

The best network sniffer & protocol analyzer out there.