Invihertz studies some subjects related to radio and every kinds of attacks like GSM Attacks, RF/wifi Keyboard sniffing, etc...

Zenk-Security French IT security-based community, participating on the most famous challenges

Ghosts In The Stack was founded by Trance and Heurs. It deals with IT security and white-hat hacking. The subjects covered are vasts : application vulnerabilty analysis, Web sites vuln analysis, shellcoding, network vulnerabilities, etc.