QUANTUM KEY DISTRIBUTION DEVICE, QUANTUM KEY DISTRIBUTION SYSTEM, AND COMPUTER PROGRAM PRODUCT

摘要

According to an embodiment, a quantum key distribution device includes a quantum key distributor, a sifter, a corrector, an identifier, a classifier, a calculator, and a privacy amplifier. The quantum key distributor obtains a photon string from a photon string of two or more intensities of light pulses. The sifter obtains pulse information indicating the light pulse to which each bit of a shared bit string corresponds. The corrector corrects an error included in the shared bit string and generates a post-correction bit string. The identifier generates error position information. The classifier classifies each bit of the post-correction bit string. The calculator calculates the error rate for each light pulse and each base using the error position information. The privacy amplifier generates a cryptographic key from the post-correction bit string on the basis of the error rate.

主权项

1. A quantum key distribution device that is connected to another quantum key distribution device by a quantum communication channel and a classical communication channel and that generates and shares an identical cryptographic key, the quantum key distribution device comprising:
a quantum key distributor to obtain a photon string by performing quantum key distribution via the quantum communication channel with respect to photons included in two or more intensities of light pulses, and obtain a photon bit string corresponding to the photon string on the basis of base information that is generated; a sifter to generate a shared bit string from the photon bit string by performing sifting based on base information of the quantum key distributor and base information of the other quantum key distribution device, and obtain pulse information indicating the light pulse to which each bit of the shared bit string corresponds; a corrector to perform error correction to correct an error included in the shared bit string and generate a post-correction bit string; an identifier to generate error position information which enables identification of a bit in the post-correction bit string from which error was corrected during the error correction of the corrector; a classifier to classify, using the pulse information and the base information, the light pulse and a base to which each bit in the shared bit string corresponds; a calculator to calculate an error rate for each of the light pulses and each of the bases classified by the classifier using the error position information; and a privacy amplifier to perform privacy amplification to compress the post-correction bit string on the basis of each of the error rates, and generate the cryptographic key.