The concept of quantum-secure readout of Physical Unclonable Functions(PUFs) has recently been realized experimentally in an optical PUFsystem. We analyze the security of this system under the strongest typeof classical attack: the challenge estimation attack. The adversaryperforms a measurement on the challenge quantum state in order to learnas much about it as he can. Using this knowledge he then tries toreconstruct the challenge and to emulate the PUF. We consider quadraturemeasurements, which are the most informative practical measurementsknown to us. We prove that even under this attack the expected number ofphotons detected in the verification mechanism is approximately a factorS + 1 too low; here S is the Quantum Security Parameter, defined as thenumber of modes in the optical system divided by the number of photonsin the challenge. The photon count allows for a reliable distinctionbetween an authentic PUF and a challenge estimation attack.

http://dx.doi.org/10.1142/S021974991350041X

B. Skoric, P.W.H. Pinkse, A. P. Mosk

2013

09/2013

Int. J. Quantum Inf.

11

135401: 1-15

quantum-secure authentication, speckle