Cyber spies have stolen tens of terabytes of design data on the US's most expensive costliest weapons system -- the $300 billion Joint Strike Fighter project. Similar breaches have been found in the Air Force's Air Traffic Control System. The attacks began as far back as 2007 and continued into 2008. The spies encrypted the data that they stole, making it difficult for investigators to know exactly what data was taken. The fact that fighter data was lost to cyber spies was first disclosed by U.S. counterintelligence chief Joel Brenner. Brenner also expressed concern about spies taking control of air traffic control systems, saying there could come a time when "a fighter pilot can not trust his radar."