HIGH-SPEED OPTICAL LINE PROTECTED FROM EAVESDROPPING BY QUANTUM NOISE Russian patent published in 2014 - IPC H04K1/00 

FIELD: physics.

SUBSTANCE: received power level of an optical signal in a link is monitored and matched with the transmitting side, selecting it to be maximally low, comparable to the level of optical quantum noise at the receiving side and where it is still possible to recover lost information bits while minimising optical losses in the optical line; a key for decrypting a bit data packet contained in the packet itself can vary from packet to packet and a cryptographic algorithm is selected such that decryption is impossible if a bit is lost from a data packet. The optical link comprises: a transmitter with an actuator, a receiving optical amplifier, a photoelectronic converter with an output narrow-band filter.

EFFECT: improved robustness against unauthorised information access by combining high data transmission rate with maximally low power of quantum bits of an encoded signal.

14 cl, 3 dwg