Nuclear proliferationGame of marbles inspires nuclear-inspection protocol
Modern cryptography combined with simple radiation detectors could allow nuclear-weapons checks to be carried out with almost complete security. That is the conclusion of scientists in the United States, who have used computer simulations to show how a beam of neutrons can establish the authenticity of a nuclear warhead without revealing any information about that weapon’s composition or design.
Child's game provides a pathway for nonproliferation // Source: philja.com
Modern cryptography combined with simple radiation detectors could allow nuclear-weapons checks to be carried out with almost complete security. That is the conclusion of scientists in the United States, who have used computer simulations to show how a beam of neutrons can establish the authenticity of a nuclear warhead without revealing any information about that weapon’s composition or design.
Current arms-control arrangements between the United States and Russia limit the number of nuclear warheads inside missiles. Future agreements, however, could require that all warheads be accounted for, including those in storage. This would rely on inspectors being able to tell a real nuclear warhead apart from a fake one — which would prevent a country from secretly stashing away some of its declared warheads.
Plutonium-239 in a concealed warhead can be revealed by exposing it to gamma rays or neutrons. This means of detection, however, would also reveal secret information about the design of the weapon, which must be kept from the inspectors to prevent nuclear proliferation.
Open to abuse
Proposed schemes to avoid this problem involve passing the detector’s output through an electronic device that strips the data of their sensitive elements, such as the precise amount of radioactive material contained in the weapon. Such techniques, however, are open to abuse. The inspector could syphon off sensitive data, while the weapon’s owner could interfere with the device and make innocuous objects appear to be nuclear warheads.
An IOP release reports that the newly proposed technique closes these loopholes by not producing any sensitive information in the first place. It is based on the “zero-knowledge proof,” in which two objects can be shown with near certainty to be identical, even though nothing is known about the objects themselves. In their work, Alexander Glaser of Princeton University and colleagues adapt a game in which a character known as Alice must prove to a second person, Bob, that the number of marbles in each of two cups she is holding is the same, without revealing what that number (N) is.
