Already back in July, at the 2015 INMM Annual Conference, we reported initial results from the first zero-knowledge differential neutron radiographic measurements. To our knowledge, this was the first demonstration of a physical zero-knowledge proof of physical properties. This proof-of-concept constitutes a small but important first step toward an efficient zero-knowledge protocol for nuclear warhead authentication where sensitive information is never measured.
For this first demonstration, we tried to implemented all key steps of a zero-knowledge inspection using 14-MeV DT neutron radiography with test items represented by patterns of steel and aluminum cubes. We were able to preload the bubble detectors with the complement of the radiograph of a reference item and, by subsequent irradiation, verify whether items presented for inspection were identical to the reference item or not. We confirmed that the results yielded “zero information” when valid items were tested and successfully identified tampered items for four different diversion scenarios.
Watch this space for updates as we evaluate new measurements and write up the journal version of the paper.