Anatoliy Sotnikov

In this work, we demonstrate a new kind of attack on laser sources in quantum key distribution systems - the optical-pumping attack. We investigated its influence on a single distributed feedback laser diode and an optically injection-locked source configuration. The spectral dependency of this attack was also examined. We managed to increase the energy of emitted pulses using attackers light at several wavelengths. The developed optical-pumping attack should be considered as a possible threat to the security of QKD systems because the increase of pulse energy leads to overestimation of secret key rate between Alice and Bob, giving more information about secret key to Eve.