Deterrence will keep a lid on cyberwar, former spy chief says

All nation states would suffer if countries engaged in cyberattacks against civilians, and world leaders including those in China and Russia are reluctant to unleash such forces, Blair, a retired U.S. Navy admiral who oversaw U.S. intelligence from 2009 to 2010, told a news conference in Tokyo.

Military and civilian systems are often intertwined, Blair said, pointing to GPS as an example of a military technology that is now used in widespread civilian applications from navigation to financial transactions.

"Should a nation state take action against the GPS system in another country in a major scale, there's no telling which way the damage would fall," Blair said, adding that the same is true with military communications that share fiber optic cables with civilian traffic.

Chinese military hackers, however, are conducting industrial espionage while preparing for conflict by implanting algorithms that could shut down networks when desired, he said.

"They're just blundering away at trying to hack in any way they can, including all your organizations, by the way," Blair told international press representatives at the Foreign Correspondents' Club of Japan.

His comments followed China's acknowledgment in March that it has a cyberwarfare unit, a disclosure that surprised few people.

Earlier this month, U.S. President Barack Obama signed an executive order allowing the U.S. government to penalize people, organizations and governments engaging in "malicious cyber-enabled activities" harming the U.S.

Blair also defended information-gathering by the National Security Agency and other U.S. intelligence groups, saying it is eclipsed by unsupervised collection of data by companies such as Google for advertising purposes.

"No innocent American" has been inconvenienced by the collection of data under Section 215 of the USA Patriot Act, which allows for bulk collection of metadata, Blair said, emphasizing that how the data are used is more important than the act of collecting.

"The way technology is going, we should be worried about the use, but the collection is sort of out of control," he said.

Apple, Facebook, Google, Evernote, Twitter, Microsoft and other tech firms have joined calls on the U.S. government not to renew the Patriot Act provision, which expires in June.

Tim Hornyak covers Japan and emerging technologies for The IDG News Service. Follow Tim on Twitter at @robotopia.