QUANTUM KEY DISTRIBUTION SYSTEM WITH UNTRUSTED CENTRAL NODE AND METHOD OF PREPARING QUANTUM STATES FOR QUANTUM KEY DISTRIBUTION PROTOCOL WITH UNTRUSTED CENTRAL NODE Russian patent published in 2025 - IPC H04L9/08 

FIELD: cryptographic mechanisms.

SUBSTANCE: invention relates to means of quantum key distribution with untrusted central node. Claimed technical result is achieved by implementing a quantum key distribution system with an untrusted central node, which comprises two transmitting units connected by fibre-optic communication to a receiving unit, in which each transmitting unit comprises a laser radiation source, generating pulses in gain switching mode, arriving at a qubit encoding unit encoding quantum information in the phase difference and/or in the time of arrival of the laser pulses and/or in the polarization of the optical pulses, which are then transmitted to an optical attenuator, which performs their attenuation to a quasi-single-photon level. Signals from each transmitting unit are transmitted to an untrusted central node comprising a beam splitter, which performs entanglement of the obtained quantum state signals; two detectors of single photons, which perform registration of incoming signals from a beam splitter.

EFFECT: high stability of the quantum key distribution system to attacks on implementation.

8 cl, 13 dwg