Detection of variable-intensity optical emission using an avalanche photodiode in photon-counting mode

Abstract

We demonstrate the possibility of blinding attacks on silicon avalanche photodiodes operating at room temperature and used in quantum cryptographic systems for the detection of single-photon radiation pulses at a wavelength of 850 nm. The parameters of different silicon avalanche photodiodes in the event of their blinding are determined. The possibility of detecting blinding attacks on avalanche photodiodes by controlling the electrical current through the photodiode is established. According to the obtained results, different radiant exposures of multiphoton optical pulses are required to imitate single-photon pulses for different avalanche photodiodes, and the duration of the optical pulses must be shorter than 1 µs. We determine that information on the properties of the avalanche photodetector used in the quantum cryptographic system is required to select the intensity of the optical emission and radiant exposure of multiphoton optical pulses for executing a blinding attack. A schematic of the experimental setup used to investigate blinding attacks and oscillograms of the output signals of avalanche photodiodes under such conditions are presented.