Comment on "Deterministic six states protocol for quantum communication" [Phys. Lett. A 358 (2006) 85]

TL;DR

This paper critically examines the security analysis of the deterministic six states protocol for quantum communication, revealing inaccuracies in previous attack detection probabilities and information gain assessments.

Contribution

It corrects and clarifies the security vulnerabilities of the 6DP protocol by reevaluating specific attack strategies and their effectiveness.

Findings

IRA detection probability is 70%, not 50%

Eve can only obtain 50% of the data in 2CNOTA

Previous security claims were inaccurate

Abstract

In [J.S. Shaari, M. Lucamarini, M.R.B. Wahiddin, Phys. Lett. A 358 (2006) 85-90] the deterministic six states protocol (6DP) for quantum communication has been developed. This protocol is based on three mutually unbiased bases and four encoding operators. Information is transmitted between the users via two qubits from different bases. Three attacks have been studied; namely intercept-resend attack (IRA), double-CNOT attack (2CNOTA) and quantum man-in-the-middle attack. In this Letter, we show that the IRA and 2CNOTA are not properly addressed. For instance, we show that the probability of detecting Eve in the control mode of the IRA is 70% instead of 50% in the previous study. Moreover, in the 2CNOTA, Eve can only obtain 50% of the data not all of it as argued earlier.