Teleportation-Based Continuous Variable Quantum Cryptography

TL;DR

This paper introduces a continuous variable quantum key distribution protocol based on quantum teleportation that is secure against certain attacks, efficient with current technology, and effective even with high optical losses.

Contribution

It presents a novel CV QKD scheme utilizing quantum teleportation that overcomes the 50% loss limitation and enables secure key generation with efficient detection and error correction.

Findings

Secure against certain incoherent attacks without 3 dB loss limit

Works deterministically with direct reconciliation

Effective beyond 50% optical loss

Abstract

We present a continuous variable (CV) quantum key distribution (QKD) scheme based on the CV quantum teleportation of coherent states that yields a raw secret key made up of discrete variables for both Alice and Bob. This protocol preserves the efficient detection schemes of current CV technology (no single-photon detection techniques) and, at the same time, has efficient error correction and privacy amplification schemes due to the binary modulation of the key. We show that for a certain type of incoherent attack it is secure for almost any value of the transmittance of the optical line used by Alice to share entangled two-mode squeezed states with Bob (no 3 dB or 50% loss limitation characteristic of beam splitting attacks). The present CVQKD protocol works deterministically (no postselection needed) with efficient direct reconciliation techniques (no reverse reconciliation) in order to generate a secure key and beyond the 50% loss case at the incoherent attack level.