German crypto specialist and and chief scientist with Berlin's SR Labs Karsten Nohl is reflected in a computer screen as he looks at photographs of USB sticks in his office in Berlin, July 30, 2014. USB devices such as mice, keyboards and thumb-drives can be used to hack into personal computers in a potential new class of attacks that evade all known security protections, Nohl revealed on Thursday. Picture taken July 30, 2014. REUTERS/Thomas Peter (GERMANY - Tags: SCIENCE TECHNOLOGY CRIME)