On Sunday, just hours after starting to run new, advanced centrifuges that can enrich uranium faster, Iran’s nuclear facility at Nantanz suffered what was termed a “suspicious” blackout. Speculation immediately began in the Israeli media that some kind of cyber attack had crippled the facility. It wouldn’t be the first time Nantanz had been targeted. In 2010, the Stuxnet worm wreaked havoc on the facility’s centrifuges, causing a huge drop in enriched uranium output. These new centrifuges could take the 20 percent enriched uranium that Iran already possesses and jack it up to bomb-grade levels (90 percent) in a matter...