They are also relentless, said Nick Levay, associate director of information security and operations at the Center for American Progress, a Washington think tank.
"Those who have been targeted by China have dealt with a certain level of persistence and seen these attacks take place over long periods of time, where all signs point back to China and it really feels like they're not even trying to hide that it's them anymore," he said.
Levay said Chinese cyber attacks noticeably escalated after the 2008 Beijing Olympics and "expanded pretty much across all sectors: the financial sector, the tech sector, the non-profits involved in government policy."
"So far when breaches occur, like the ones with Google, the people who were breached condemn the attacks and say they were attributable to China and China turns around and denies that anything happened at all," said Levay.
"So far there hasn't been a downside for them (China)," he said, suggesting that cyberspace be made a formal part of military dialogue between the United States and China.