State Decoding in Multi-Stage Cryptography Protocols

TL;DR

This paper introduces a practical quantum tomography method for decoding photon states in multi-stage cryptography protocols, requiring specific filters and photon counts based on polarization angles.

Contribution

It presents a new quantum tomography approach tailored for multi-stage cryptography, optimizing photon filtering based on polarization angles.

Findings

Requires m filters for 2m polarization angles

Needs m^2 photons per filter

Applicable when polarization angles are on a fixed plane

Abstract

This paper presents a practical method of quantum tomography for decoding the state of photons in a multistage cryptography protocol. This method works if the polarization angles are defined on a fixed plane, as is assumed in several quantum cryptography protocols. We show if there are 2m polarization angles in a fixed plane, we need m number of filters and m2 number of photons through each filter.