Alexander's speech came the same day columnist Glenn Greenwald at The Guardian published a new report based on secret NSA documents provided by ex-NSA contractor Edward Snowden that detailed a different surveillance program known as XKeyscore -- a program an NSA briefing boasted collects "nearly everything a user does on the internet."
It was also today that James Clapper, the Director of National Security, announced the government would declassify some of the programs made public by Edward Snowden to provide the public a better idea of what the programs are designed to do.
At one point in the speech, Alexander revealed that 20 of the 6,000 NSA cryptologists sent to Iraq and Afghanistan had been killed in action and likened their mission abroad to the analysts' mission at home.
"These are the same people, who take that same oath to uphold and defend the Constitution, are the ones who run these [surveillance] programs," he said.
Alexander Reveals Numbers on NSA vs. Terrorism
During his speech, Alexander also provided new details about the 54 terror-related activities the NSA programs have allegedly helped stop, referring to 42 of them as "plots."
Of the 54 incidents, Alexander said, 13 took place in the U.S., 25 in Europe, five in Africa and 11 in Asia. New leads were provided by an NSA surveillance program in approximately half of those, he claimed.
Similar previous claims by U.S. officials have been called into question, as it was unclear how large of a role the NSA programs actually played. One such claim, made by FBI deputy director Sean Joyce last month, was that the NSA programs helped thwart a plot against the New York Stock Exchange, though court documents reviewed by ABC News showed the plot had fizzled out without the NSA's help.
Before receiving a resounding applause from the audience at the end of his address, Alexander offered a challenge to those who don't like the way the NSA is working now: Help them find a way to do it better.
"This is the greatest gathering of technical talent anywhere in the world," he said. "Maybe you have some ideas of how to do it better."