The information that former NSA contractor Edward Snowden and others leaked has created what a top U.S. intelligence official calls a "virtual university" for terrorists, spies, hackers, smugglers and many others seeking to attack or exploit the U.S. Rick Ledgett, deputy director of the NSA, says those nefarious people and the organizations they represent have made adjustments "in order to avoid being detected by NSA." Ledgett said Snowden's leaks alone caused "significant" risk to the safety of Americans everywhere.