Fake state attack on practically decoy state quantum key distribution

TL;DR

This paper analyzes the security vulnerabilities of practical decoy state quantum key distribution under fake state attacks, revealing that Eve can exploit threshold detectors to compromise security.

Contribution

It provides a detailed analysis showing that decoy state QKD is vulnerable to fake state attacks using threshold detectors in practical scenarios.

Findings

Eve needs photon-number-resolving instruments for certain attacks

Threshold detectors can be exploited in practical implementations

Decoy state QKD may be insecure under fake state attacks

Abstract

In this paper, security of practically decoy state quantum key distribution under fake state attack is considered. If quantum key distribution is insecure under this type of attack, decoy sources can not also provide it with enough security. Strictly analysis shows that Eve should eavesdrop with the aid of photon-number-resolving instruments. In practical implementation of decoy state quantum key distribution where statistical fluctuation is considered, however, Eve can attack it successfully with threshold detectors.