In today's podcast we look at studies of how ISIS actually operates online. Apparently they do so much the way crooks do—by abusing legitimate services. But when it comes to encryption, the jihadists seem to be rolling their own. Ransomware updates and warnings—the FBI reminds victims not to pay. The group that hit the Qatar National Bank may be preparing release of another bank's information. Infrastructure companies invest to shore up cyber defenses. We hear from the University of Maryland's Jonathan Katz on digital signatures, and we talk with the Denim Group's John Dickson about power grid security.