Nuclear disarmament

Nuclear physicists may have just invented a ‘zero-knowledge’ warhead inspection system

Nuclear disarmament is all about trust—a hard thing for rival political powers to build, even under the best of circumstances. Today, a team of researchers revealed something that might make that process easier: a new technique that nuclear inspectors can use to verify whether a warhead is active, inactive, or a fake—all without learning anything about its design. "This is something that has been an open problem for 50 years,” says study author and Massachusetts Institute of Technology in Cambridge nuclear policy expert R. Scott Kemp, who adds that it may be “the first technical solution” to the problem.

Nuclear powers still possess more than 15,000 such weapons, according to the Federation of American Scientists. Although agreements such as 2010's New Strategic Arms Reduction Treaty have sought to limit U.S. and Russian stockpiles of nuclear missiles, no system has been successfully implemented to verify whether a nuclear warhead has been dismantled without revealing design secrets. Previous methods that kept those secrets safe were all vulnerable to cheating, Kemp says.