The former chief of the National Counterterrorism Center told CNN that National Security Agency secrets made public by Edward Snowden have altered how terrorists communicate with each other — in some cases, resulting in U.S. intelligence losing track of potentially dangerous individuals.
"They've changed how they encrypt their communications and adopted more stringent encryption techniques," he told CNN. "They've changed service providers and email addresses and they've, in some cases, just dropped off all together."
[sharequote align="center"]"...it's made it harder for us to collect against them."[/sharequote]
"Again, they suspected we had this capability before ... but it's really become a real concerted effort now by a number of these targets, people we were following, and it's made it harder for us to collect against them," Olsen added, noting that the U.S. has "lost collection against some individuals" that they were "concerned about."