[20p-A404-1~18] 3.9 Optical quantum physics and technologies (formerly 3.10)

[20p-A404-11] Differential quadrature phase shift quantum digital signature

〇Kyo Inoue¹, Toshimori Honjo² (1.Osaka Univ., 2.NTT Labs.)

Keywords:quantum communication, quantum digital signature, differential quadrature phase shift

Quantum digital signature (QDS) is a quantum technology that confirms whether a received message is legitimate by comparing a signature key attached to the message and an authentication key publicly distributed in advance. This paper proposes a novel QDS protocol wherein a message sender broadcasts a weak coherent pulse train with four phases and each recipient creates an authentication key by receiving the pulses with two delay interferometers followed by photon detectors. The key distribution stage is accomplished with this signal transmission, and no post-processing is performed, featuring simplicity compared with conventional QDS protocols.