According to the Washington Post, Chinese spies have allegedly hacked into the designs of many of the United States' advanced weapons systems and platforms, including those for F/A-18 Hornet fighter jets, the Patriot missile system and Black Hawk helicopters.

25 of these hacked designs were in programs critical to American missile defenses, combat aircraft and ships. In the public part of the report (PDF), the Defence Science Board has already warned that the Pentagon wouldn't be able to defend itself in the event of a full-scale cyber-conflict.

"After conducting an 18-month study, this Task Force concluded that the cyber threat is serious and that the United States cannot be confident that our critical Information Technology (IT) systems will work under attack from a sophisticated and well-resourced opponent utilizing cyber capabilities in combination with all of their military and intelligence capabilities (a 'full spectrum' adversary)," the report said.

The Defence Science Board didn't claim that Chinese agents were behind the cyber attacks, but top military and industry sources who knew about the breaches told the paper that the hacks were part of a growing Chinese campaign of espionage.

China has of course denied the allegations and has fired back that the US is using cyber attacks against them.