WASHINGTON (CN) - Ending bulk-data collection will significantly hurt the National Security Agency's operational capabilities, NSA Director Admiral Michael Rogers told Congress on Thursday, pointing to the rise of cybersecurity threats.
In a rare public session, hours after Pope Francis addressed Congress , Rogers appeared before the Senate Intelligence Committee to discuss some of the challenges the agency faces as it transitions to a new data-collection system.
The NSA's move comes in connection to the Nov. 29 deadline of the USA Freedom Act , which revoked the authority the agency had to gather the phone records of millions of Americans under the Patriot Act.
Sen. Richard Burr, a North Carolina Republican who chairs the committee, invited Rogers to use the public hearing "to separate the myth of the NSA from the reality of the NSA," in the wake of the fallout from the Edward Snowden leaks.
Rogers assured the Senate: "We do not indiscriminately collect."
"Everything we do is driven by the law and a set of priorities as to exactly what we do and what we focus on," Rogers added, saying NSA efforts are designed to defend the nation, not invade people's privacy.
The mostly sympathetic committee members heaped praise on the agency for its intelligence gathering, and its use of bulk phone data to thwart terror attacks on U.S. soil, claims that have been widely disputed by organizations like the Electronic Frontier Foundation.
Rogers meanwhile insisted that bulk data collection has intelligence value, citing a report that the National Academy of Sciences released in January, which concluded that no technological replacement for bulk-data collection exists.
Hinting that this will hamper counter-terrorism efforts, Rogers said terror groups, including the Islamic State in Iraq and the Levant and al-Qaida, have adopted more behavioral changes in the past two years than he has seen from any other target.
"They actively reference some of the compromises and media leaks of the last couple of years," Rogers said. "And we know they have achieved a level of insight as to what we do, how we do it and the capabilities we have, that quite frankly they didn't have" before.
Compounding the harms from restricting bulk data collection, Rogers said technological advances - including the proliferation of encrypted communication - make it more difficult to figure out what these groups are doing.
Sen. Ron Wyden, D-Ore., reminded Rogers that President Barack Obama's advisory committee disagreed with Rogers on the effectiveness and value of bulk data gathering, citing page 104 of the committee's 2013 report.
"The information contributed to terrorist investigations by the use of section 215 telephony meta-data was not essential to preventing attacks and could readily have been obtained in a timely manner using conventional section 215 orders," the report said .
Under the USA Freedom Act, the NSA will no longer collect phone metadata directly from phone companies and conduct its own data queries. Instead, the agency will have to get a court order to ask the phone companies to query their own data.
