Comment on "Quantum Key Distribution in the Holevo Limit"

TL;DR

This paper critiques a quantum key distribution protocol, demonstrating that an eavesdropper can distinguish quantum keys without detection, challenging the protocol's security assumptions and the generality of no-cloning for orthogonal states.

Contribution

It reveals vulnerabilities in Cabello's QKD protocol and questions the broader applicability of no-cloning principles for orthogonal states.

Findings

Eavesdropper can distinguish keys without detection

The proposed attack applies beyond Cabello's protocol

No-cloning for orthogonal states may not prevent eavesdropping

Abstract

In a Letter, Cabello proposed a quantum key distribution (QKD) Protocol which attended to Holevo limit. In this comment, we show that Eve could use a simple plan to distinguish among quantum keys, without being detected by Alice and Bob. In following, we show that our approach is not restricted to Cabello Protocol. With attention to our Eavesdropping approach, it seems that Mor's arguments for no-cloning principal for orthogonal states is not general enough to avoid eavesdropping.