Device independent quantum key distribution secure against coherent attacks with memoryless measurement devices

TL;DR

This paper extends the security proof of device independent quantum key distribution to include arbitrary attacks with memoryless measurement devices, broadening its practical security guarantees.

Contribution

It generalizes previous security proofs to cover more realistic scenarios where measurement devices have no memory, using a reduction to qubit strategies and existing proof techniques.

Findings

Security proof extended to arbitrary attacks with memoryless devices

Reduction of complex strategies to qubit strategies

Security established based on previous proofs and techniques

Abstract

Device independent quantum key distribution aims to provide a higher degree of security than traditional QKD schemes by reducing the number of assumptions that need to be made about the physical devices used. The previous proof of security by Pironio et al. applies only to collective attacks where the state is identical and independent and the measurement devices operate identically for each trial in the protocol. We extend this result to a more general class of attacks where the state is arbitrary and the measurement devices have no memory. We accomplish this by a reduction of arbitrary adversary strategies to qubit strategies and a proof of security for qubit strategies based on the previous proof by Pironio et al. and techniques adapted from Renner.