Earlier this month, during a Senate Judiciary Committee hearing, Senator Patrick Leahy pressed the NSA's director, General Keith Alexander, on whether the figures that are used to support data collection programs, notably the bulk collection of phone records, are accurate.

Throughout the summer, the Obama Administration and NSA officials have repeatedly told the public how the controversial Sections 215 and 702 (also known as PRISM) of the Patriot Act, were used to stop terrorist plots. At issue is how the two sections are used for various intercept programs, including business records collections. But administration officials as well as the NSA have consistently repeated the point that such intercept programs are managed with strict oversight.

At the Black Hat/Defcon security conference, General Alexander told attendees that 54 terror plots were stopped because of records collected under Sections 215 and 702, and of those 13 of them were in the U.S. Moreover, General Alexander noted that of the 13 plots halted in the U.S., 12 of them were directly linked to the intercept programs.

However, when questioned by Senator Leahy, General Alexander confirmed that only "one, perhaps two" terror plots were halted by business records collections.

Questioning General Alexander directly, Senator Leahy asked, "Would you agree that the 54 cases that keep getting cited by the administration were not all plots, and of the 54 only 13 had some nexus to the U.S.? Would you agree with that, yes or no?"

To this, General Alexander responded with the affirmative.

Exaggerated at hacker conference

When asked by Senator Leahy to confirm NSA Deputy Director Inglis' comments to the Judiciary Committee that "there was really only one example of a case where, but for the use of Section 215 bulk phone records collection, terrorist activity was stopped," General Alexander's remarks walked back his comments to Black Hat attendees.

Gen. Keith Alexander

"He's right. I believe he said two, Chairman (Senator Leahy), I may have that wrong, but I think he said two," General Alexander responded. "And I'd like to point out that it could only have applied in 13 of the cases because of the 54 terrorist plots, or events, 13 occurred in the U.S."

Senator Leahy interrupted at that point, noting that the contradiction of metrics and stats does nothing for the credibility of the program itself. In defense, Director of National Intelligence, James Clapper, (who was also testifying with General Alexander) commented that the number of plots foiled shouldn't be the only measurable metric for success, noting that there was another metric that is very important, the "piece of mind metric."

Security blanket or not, not everyone is buying the administration's explanations. In a blog post on grahamcluley.com, F-Secure's Mikko Hypponen, noted that the public should be outraged by the NSA's intercept programs, not just worried.

"But don't get me wrong. I do understand the need for doing both monitoring and surveillance. If somebody is suspected for running a drug ring, or planning a school shooting or participating in a terror organization, he should be monitored, with a relevant court order. However, that's not what PRISM is about. PRISM is not about monitoring suspicious people. PRISM is about monitoring everyone," he wrote.

"It's about monitoring people that are known to be innocent. And it's about building dossiers on everyone, eventually going back decades. Such dossiers, based on our internet activity will build a thorough picture of us. And if the powers-that-be ever need to find a way to twist your hand, they would certainly find something suspicious or embarrassing on everyone, if they have enough of their internet history recorded."

This story, "PRISM's value was overstated, NSA chief acknowledges" was originally published by CSO .