LAS VEGAS—National Security Agency Director Gen. Keith Alexander defended the federal government's collection of phone and Internet records in a ballroom full of hackers on Wednesday, offering new details on how the programs have blocked terrorist activity.
Mr. Alexander's speech at the Black Hat hacker conference came as the Obama administration declassified new documents on the spy agency's electronic snooping and the U.K.-based Guardian newspaper published yet more leaked documents from former NSA contractor Edward Snowden.
The four-star general sought to portray the discussion around the government's spying as hyperbolic. He offered new information—along with colorful language—about the program's oversight provisions and how many terrorist plots it has blocked.
In total, Mr. Alexander said, the NSA's collection of phone-call metadata and Internet records of foreigners had resulted in the disruption of 42 terrorist plots.
The general added that there are just 35 analysts at the NSA authorized to query a database of U.S. phone records.
"What you're hearing is, 'Well, they could,'" Mr. Alexander said of speculation that the agency is combing through all U.S. phone calls and Internet traffic. "The fact is, they don't."
His address here took place amid new tension between the intelligence services and the hacker community, which often provides top recruits to the NSA, the nation's electronic eavesdropper. Following new disclosures about the NSA's domestic surveillance practices, many at Black Hat have questioned whether they want to put their skills to use for the government.
At one point, someone in the audience yelled, "Bulls—," and added, "You lied to Congress. Why would we believe you're not lying now?"
Later, Mr. Alexander addressed the heckler indirectly. "That's no bulls—. Those are facts," he said, referring to NSA's internal auditing standards.
The audience appeared mostly to be on his side. After another heckler suggested that the general "read the Constitution," he quipped back, "I have. You should, too."
The audience applauded loudly.
Black Hat is one of two annual hacker conferences taking place in Las Vegas this week. It maintains strong ties with large computer-security companies that are likely more friendly to Mr. Alexander's message.
The other conference, Def Con, is viewed as a more mischievous affair. The general addressed that crowd last year in jeans and a black T-shirt. At Black Hat, he spoke in military uniform.
Write to Danny Yadron at [email protected]
