Transmitting device, receiving device, quantum key distribution method, and quantum key distribution program for quantum key distribution system

A receiving device for a quantum key distribution system, comprising:

• a decoding unit configured to receive, from a transmitting device, a train of optical pulses which has been encoded and subjected to N types of intensity modulation having mutually different intensities, with different timings, where N is an integer which is not less than three, the decoding unit producing a data sequence obtained by decoding the train of optical pulses;
• and
• a second key distillation processing unit configured to generate an encryption key based on a data sequence obtained by removing data obtained from optical pulses having a specific modulation pattern from the data sequence obtained by the decoding.

A quantum key distribution method comprising generating an encryption key based on a data sequence obtained by removing data obtained from optical pulses having a specific modulation pattern from a data sequence used when a train of optical pulses are subjected to encoding and N types of intensity modulation having mutually different intensities, where N is an integer which is not less than three.

A quantum key distribution method comprising:

• receiving, from a transmitting device, a train of optical pulses which has been encoded and subjected to N types of intensity modulation having mutually different intensities, with different timings, where N is an integer which is not less than three, to produce a data sequence obtained by decoding the train of optical pulses;
• and
• generating an encryption key based on a data sequence obtained by removing data obtained from optical pulses having a specific modulation pattern from the data sequence obtained by the decoding.

A non-transitory computer readable medium for storing a quantum key distribution program for making a computer function as:

• means for generating an encryption key based on a data sequence obtained by removing data obtained from optical pulses having a specific modulation pattern from a data sequence used when a train of optical pulses are subjected to encoding and N types of intensity modulation having mutually different intensities, where N is an integer which is not less than three.

A non-transitory computer readable medium for storing a quantum key distribution program for making a computer function as:

• means for generating an encryption key based on a data sequence obtained by removing data obtained from optical pulses having a specific modulation pattern from a data sequence obtained by decoding a train of optical pulses which has been encoded and subjected to N types of intensity modulation having mutually different intensities, with different timings, where N is an integer which is not less than three.