have been holding almost weekly meetingsin an effort to finish an agreement on nuclear weapons.However, a website called The Intercept saysthat a "cyber war," attacks against computer networks,is taking place behind the scenes.The website takes some of its informationfrom secret U.S. government documents made public by Edward Snowden.It published details of a U.S. National Security Agency paper,written two years ago.The NSA paper calls for a stronger U.S. answerto Iran's improved cyber warfare abilities.The report says Iran learned from a virus called Stuxnetthat was placed into its nuclear program.The virus allegedly was put thereby U.S. and Israeli intelligence services in 2012.David Stupples of City University, Londonis a cyber-warfare expert.He says the incident may have shown Iranian leadersthe value of cyber warfare, compared to controversial,costly and dangerous nuclear weapons.Iran has "now realized they have a much stronger weapon at hand,"Mr. Stupples said.He added that Iran "can continually attack and continually get payoffs from their activities quite cheaply."A basic cyberattack means a computer attacker closes down a website.Real problems, however, result when cyberattacks steal or destroy data.That is what happened in the attack on Sony Pictures last year,reportedly by North Korea.A year ago, the head of the NSA, Admiral Mike Rogers,told Congress that cyber warfare is here to stay."Clearly, cyber will be an element of almost any crisiswe are going to see in the future," said Admiral Rogers.He added that he believes cyber warfarewas used in Ukraine, Syria and Georgia."It increasingly is becoming a norm," he said.Cyberattacks are inexpensive, secret, and can be denied.Those are some of the reasons that could make themmore appealing to terrorists and governments,instead of using conventional or nuclear weapons.