Linear Cryptanalysis through the Lens of Clauser-Horne-Shimony-Holt Game

TL;DR

This paper introduces a novel application of the CHSH game from quantum cryptography to enhance classical linear cryptanalysis, demonstrating improved bias exploitation on the SIMON cipher and suggesting broader implications for cryptanalysis methods.

Contribution

It presents a new approach using the CHSH game to improve linear cryptanalysis of symmetric ciphers, bridging quantum game theory and classical cryptanalysis.

Findings

Bias improved from 0.25 to 0.35 using the CHSH game

Application demonstrated on the SIMON lightweight cipher

Potential extension to differential cryptanalysis

Abstract

Application of CHSH game in Linear Cryptanalysis is presented. Till date, the known usage of CHSH game in Quantum Cryptology is to verify the device independence of the protocols. We observed that the classical symmetric ciphers having the bias equal to 0:25 can be improved to 0:35 exploiting the game which indicates clear improvement over existing Linear and Differential cryptanalysis. In the present initiative, we showed the application of the game in linear cryptanalysis on a lightweight cipher named SIMON. However, the approach can be extended to Differential cryptanalysis too. This observation opens a new direction of research in quantum cryptography.