The US has not gained much success in persuading Beijing to stop its hackers, even as American officials and security experts have long known that China is the main source of cyber attacks on the United States.
According to the New York Times, two recent developments, however, should raise the political costs for China and may cause it to alter its calculus.
Refusal to change its conduct could make its relations with the United States even more difficult than they are.
On Tuesday, a new report from Mandiant, an American computer security firm, publicly documented an explicit link between Chinese hackers and the People's Liberation Army.
The report cited a growing body of digital forensic evidence that most of the attacks on American corporations, organizations and government agencies originate in and around a 12-story office tower on the outskirts of Shanghai that is the headquarters of P.L.A. Unit 61398, the report said.
According to the report, Mandiant tracked individual members of the most sophisticated of the Chinese hacking groups, known as "Comment Crew" or "Shanghai Group," to the headquarters of the military unit, which is central to China's computer espionage operations.
It followed "Comment Crew" for six years, monitoring 141 attacks by looking at Web domains, malware, Internet protocol addresses and embedded codes.
Reporters for The Times confirmed the evidence contained in the report with American intelligence officials who said they have tapped into the activity of the army unit for years.
Chinese officials denounced the report, but their reaction was hardly a denial.
In a second development that could further raise the stakes for Beijing, Washington decided to share with American Internet providers and antivirus vendors information about the unique signatures of the largest of the Chinese groups, including those originating from the area where Unit 61398 is based.
According to the report, the government warnings will not link the hackers and their computers to the Chinese Army per se, but the effects will be felt when the hackers and computers are denied access to American networks, as many of the Internet providers and antivirus vendors are expected to do.
American officials are increasingly concerned about cyber attacks intended not just to steal corporate secrets but also, as President Barack Obama said in his recent State of the Union address, to "sabotage our power grid, our financial institutions, our air traffic control systems," the report said.
As a defensive measure, Obama last week signed an executive order promoting increased information-sharing about cyber threats between the government and private companies that oversee the country's critical infrastructure, including its electrical power grid, gas lines and waterworks.
Congress still has not acted on legislation setting minimum requirements for how this infrastructure should be protected.
China and the United States have to cooperate on numerous international security issues, but that won't happen if they end up in a cyber war.
Publicizing China's transgressions and blocking Internet access to hackers should be a warning to Beijing.
Washington is right to defend its interests. But the two nations need to take the lead in negotiating new international understandings about what constitutes cyber aggression and how governments should respond, the report added. (ANI)