Quantum hacking: how Eve can exploit component imperfections to control yet another of Bob´s single-photon qubit detectors

In this study, we investigated several possible attacks that an eavesdropper could launch against cryptosystems equipped with yet another commonly used silicon photon counting detector module operating with active quenching and manufactured by Perkin Elmer (model SPCM-AQR). We showed that when the avalanche photo-diode (APD) of the detector gets illuminated with bright optical pulses (instead of single photons), the voltage at which the APD is biased drops by more than 12-14 V if the repetition rate of the bright pulses is large enough (above 70kHz here).