Plans Cyber Shield for Utilities, Companies

The federal government is launching an expansive program dubbed "Perfect Citizen" to detect cyber assaults on private companies and government agencies running such critical infrastructure as the electricity grid and nuclear-power plants, according to people familiar with the program.

The surveillance by the National Security Agency, the government's chief eavesdropping agency, would rely on a set of sensors deployed in computer networks for critical infrastructure that would be triggered by unusual activity suggesting an impending cyber attack, though it wouldn't persistently monitor the whole system, these people said.

Defense contractor Raytheon Corp. recently won a classified contract for the initial phase of the surveillance effort valued at up to $100 million, said a person familiar with the project.