Kali (http://www.kali.org/) is a Linux distribution derived from Debian (as is Raspbian) designed for digital forensics and penetration testing.

Kali comes preinstalled with several software packages designed for testing the security of computer networks. These utilities allow the user to crack passwords, break into wireless networks, and perform port scans of someone's computer. Some of the tools included in Kali are shown in the following image: