Privacy for Quantum Annealing. Attack on Spin Reversal Transformations in the case of cryptanalysis

TL;DR

This paper reveals that spin reversal transformations, intended to enhance privacy in quantum annealing, can be exploited to recover original problems, especially in cryptanalysis scenarios like attacking the E0 cipher.

Contribution

It demonstrates that SRT does not guarantee privacy and provides a method to recover original problems from transformed Ising models in cryptanalysis contexts.

Findings

SRT can be exploited to recover original problems in quantum annealing.

The method is effective for small and full-scale problems.

Privacy guarantees of SRT are limited in cryptanalysis applications.

Abstract

This paper demonstrates that applying spin reversal transformations (SRT), commonly known as a sufficient method for privacy enhancement in problems solved using quantum annealing, does not guarantee privacy for all possible cases. We show how to recover the original problem from the Ising problem obtained using SRT when the resulting problem in Ising form represents the algebraic attack on the $E_0$ stream cipher. A small example illustrates how to retrieve the original problem from that transformed by SRT. Moreover, we show that our method is efficient also for full-scale problems.