Detecting an Eavesdropper in QKD Without Public Bit Comparison

TL;DR

This paper introduces a novel method for detecting eavesdroppers in quantum key distribution (QKD) that avoids public bit comparison by utilizing duplex channels and bit transport, enhancing security detection efficiency.

Contribution

It proposes a new eavesdropper detection technique in QKD that does not rely on public bit comparison, using only basis choices and filtered bits for error detection.

Findings

Filtered bits can reveal errors without security compromise

Method improves upon standard BB84 by eliminating the need for random sampling

Eavesdropper detection is more efficient and secure

Abstract

We present a method for determining the presence of an eavesdropper in QKD systems without using any public bit comparison. Alice and Bob use a duplex QKD channel and the bit transport technique for relays. The only information made public is the respective basis choices which must be revealed in standard QKD systems anyway. We find that every filtered bit can be used to determine the presence of errors without compromising the security. This is an improvement on using a random sample in the standard BB84 protocol.