The National Security Agency is working with Internet-service providers to figure out how to stop cyberattacks like the ones that have recently hit defense contractors and government agencies. The NSA is providing Internet carriers with data on suspicious network behavior and malicious code signatures that the carriers can use to scan traffic going to 15 major contractors. The collaboration capitalizes on the Internet carriers' superior ability to monitor large volumes of traffic. It's also intended to allay privacy concerns, because the government itself isn't monitoring private-sector traffic. Civil-liberties advocates are worried that a provision in the White House's recent cybersecurity proposal would open the door to cooperative surveillance by the public and private sector.