Consistency of shared reference frames should be reexamined

TL;DR

This paper critiques recent quantum cryptography protocols for reference frame transmission, revealing potential security flaws and emphasizing the need to reexamine the consistency of shared reference frames.

Contribution

It identifies a vulnerability in existing protocols where eavesdroppers can alter reference frames undetected, and discusses methods to verify their consistency.

Findings

Eavesdroppers can change transmitted reference frames without detection.

The problem differs from previous quantum cryptography security issues.

Methods to check reference frame consistency are discussed.

Abstract

In a recent Letter [G. Chiribella et al., Phys. Rev. Lett. 98, 120501 (2007)], four protocols were proposed to secretly transmit a reference frame. Here We point out that in these protocols an eavesdropper can change the transmitted reference frame without being detected, which means the consistency of the shared reference frames should be reexamined. The way to check the above consistency is discussed. It is shown that this problem is quite different from that in previous protocols of quantum cryptography.