  Boson sampling is a problem for which quantum devices could prove to go
beyond classical computing using only linear optics and photon preparation and
counting. While theoretically important, there is a lack of practical
applications for this task. This paper presents a way to turn any boson
sampling device for which there are certain fabrication limits into a
physically unclonable function which could be used in identification systems
and other security protocols. For a minimum fabrication error, there are
scenarios for which the photon distribution at the output of two different
devices has a minimum distance and they can be told apart. When compared to
classical PUFs these linear optical tokens have the advantage that, for the
right choice of parameters, there is a computational guarantee that no
classical computer can simulate the output. The paper describes the basic
limitations of boson sampling which allow these results and gives a possible
choice for a challenge-response identification protocol. This gives a direct
application of boson sampling which could be simpler than solving the general
problem.
