Comment on "Scheme of the arrangement for attack on the protocol BB84"

TL;DR

This paper critiques a recent proposed attack on the BB84 quantum key distribution protocol, demonstrating that the attack fails under standard quantum mechanics due to the impossibility of perfect state discrimination.

Contribution

The paper clarifies that the proposed weak measurement attack on BB84 is ineffective, reaffirming the security of the protocol against such attacks.

Findings

Weak measurement cannot perfectly discriminate BB84 states

The proposed attack does not succeed under standard quantum mechanics

Reinforces BB84's security against this attack

Abstract

In a recent paper (Scheme of the arrangement for attack on the protocol BB84, Optik 127(18):7083-7087, Sept 2016), a protocol was proposed for using weak measurement to attack BB84. This claimed the four basis states typically used could be perfectly discriminated, and so an interceptor could obtain all information carried. We show this attack fails when considered using standard quantum mechanics, as expected - such ``single-shot" quantum state discrimination is impossible, even using weak measurement.