US cyberweapons, effective against N Korea, fail to muzzle IS

Jihadists use social media, computers not to develop weapons but to recruit, coordinate attacks

America’s fast-growing ranks of secret cyberwarriors have in recent years blown up nuclear centrifuges in Iran and turned to computer code and electronic warfare to sabotage North Korea’s missile launches, with mixed results.

But since they began training their arsenal of cyberweapons on a more elusive target, internet use by the Islamic State (IS), the results have been a consistent disappointment, American officials say. The effectiveness of the nation’s arsenal of cyberweapons hit its limits, they have discovered, against an enemy that exploits the internet largely to recruit, spread propaganda and use encrypted communications, all of which can be quickly reconstituted