Faking photon number on a transition-edge sensor

• Main Author: Chaiwongkhot P.
• Other Authors: Mahidol University
• Format: Article
• Published: 2023
• Subjects: Physics and Astronomy
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/86907

We study potential security vulnerabilities of a single-photon detector based on superconducting transition-edge sensor. In one experiment, we show that an adversary could fake a photon number result at a certain wavelength by sending a larger number of photons at a longer wavelength, which is an expected and known behaviour. In another experiment, we unexpectedly find that the detector can be blinded by bright continuous-wave light and then, a controlled response simulating single-photon detection can be produced by applying a bright light pulse. We model an intercept-and-resend attack on a quantum key distribution system that exploits the latter vulnerability and, under certain assumptions, able to steal the key.