Pattern Based Quantum Key Distribution using the five qubit perfect code for eavesdropper detection

TL;DR

This work introduces a pattern-based QKD protocol that encodes a logical qubit across blocks of five physical qubits using the five-qubit perfect code and a pre-shared, two-pattern set $S= \{P0, P1\}$ drawn from $120$ permutations to detect eavesdropping. By replacing basis ambiguity with pattern ambiguity, the protocol ensures that Eve must determine the encoding pattern per block, with the Holevo bound yielding $\chi(X:E)=0$ unless pattern information is known, and practical information extraction relegated to classical pattern guessing. The analysis covers classical guessing performance, misapplied error correction effects, and implementation-level PNS-attack considerations, highlighting stronger resilience in quantum-transducer-based realizations versus direct photonic encoding. The results demonstrate robust eavesdropper detection via a near-deterministic multi-qubit error signature and offer practical security pathways through pattern updates and distance-3 code properties.

Abstract

I propose a new quantum key distribution protocol that uses the five qubit error correction code to detect the presence of eavesdropper reliably. The protocol turns any information theoretical attacks into a classical guess about the pattern. The logical qubit is encoded with a specific pattern into a block of five physical qubits. The security of the protocol relies on the correct pattern choice of Alice and Bob. Decoding with any wrong pattern choice increases multi qubit error rate and the 5 qubit code transforms an eavesdropper's logical disturbance into a signature that is detectable and distinguishable from natural channel noise up to a certain distance.