More than 30 months after the disclosure of a government program to help secure critical infrastructure, digital rights groups continue to have questions about whether the intent of the system is to monitor private networks.

On Jan. 2 the Electronic Privacy Information Center (EPIC) published 190 pages of documents released by the National Security Agency under a Freedom of Information Act (FOIA) request.

The documents confirm key details of the program, known as PerfectCitizen, which was revealed by The Wall Street Journal in an article published in July 2010. The project, for example, includes a major effort to find and remediate vulnerabilities in sensitive control systems (SCS). Technology giant Raytheon received the contract for the program valued at approximately $100 million.

Yet the redacted sections of the documents continue to raise questions. The NSA whited out key parts of three of the five technical requirements that set the scope of the program. In a list of the skills needed by specialized software engineers for PerfectCitizen, many of the descriptions requested by the NSA are similarly redacted.

"There is something going on here, and we need more information to confirm the extent of this program," said Jeramie Scott, National Security Fellow with the Electronic Privacy Information Center (EPIC), which filed the FOIA request for the documents.

Scott did not specify what the missing sections may indicate, but said that the information is important for U.S. citizens to know.

The release of the information comes more than two years after The Wall Street Journal described PerfectCitizen as a system that "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."

At the time, the NSA criticized the WSJ report as an inaccurate portrayal of the program. Responding to the article, the NSA released a statement to several media outlets, including eWEEK.

"Specifically, it does not involve the monitoring of communications or the placement of sensors on utility company systems," NSA spokesperson Judith Emmel said in the statement at the time. "This contract provides a set of technical solutions that help the National Security Agency better understand the threats to national security networks, which is a critical part of NSA's mission of defending the nation."

The project, first issued as a proposal in September 2009, aims to protect the sensitive control systems that collect data and automate the operations of power utilities. The agency's proposal for PerfectCitizen called for companies who bid on the project to be prepared to investigate various control systems, find vulnerabilities in those systems and develop ways of defending the networks. Still, other aspects of the system are missing from the document.

An importance of protecting sensitive networks is made quite clear, however.

"The prevention of a loss due to a cyber or physical attack, or recovery of operation capability after such an event, is crucial to the continuity of the DOD (Department of Defense), the IC (Intelligence Community), and the operation of SIGINT (signals intelligence) systems," one of the documents states.

The Electronic Privacy Information Center has not yet decided whether it will pursue an appeal of the redactions in the document. FOIA appeals are generally not granted unless they are accompanied by legal action.