U.S officials have long complained about countries that systematically hack into U.S. computer networks to steal valuable data, but until recently they did not name names.

In the last few months, that has changed. China is now officially one of the cyber bad guys and probably the worst.

“We know and there’s good evidence … of very deliberate, focused cyber espionage to capture very valuable research and development information, or innovative ideas, or source code or business plans for their own advantage,” says Mike McConnell, a former director of national intelligence and before that the director of the National Security Agency.

It’s the Chinese he’s talking about, though other countries also engage in cyber espionage to gain a competitive edge. Russia, for example, but China stands out as especially aggressive.

“China does not care what other people think,” says Richard Bejtlich, the chief security officer at MANDIANT, a company that helps firms deal with cyber intrusions. “Culturally they are very interested in being seen as responsible, but when it comes to their actual work on the ground; if you try kicking them out of your network on a Friday, they’re back on a Monday.”

The increased willingness of the U.S. government to point a finger at the Chinese dates from an official report released last October that identified them “as the world’s most active and persistent perpetrators of economic espionage.”

via China’s Hacking Of U.S. Remains A Top Concern : NPR.