Improved DIQKD protocols with finite-size analysis
Abstract
The security of finite-length keys is essential for the implementation of device-independent quantum key distribution (DIQKD). Presently, there are several finite-size DIQKD security proofs, but they are mostly focused on standard DIQKD protocols and do not directly apply to the recent improved DIQKD protocols based on noisy preprocessing, random key measurements, and modified CHSH inequalities. Here, we provide a general finite-size security proof that can simultaneously encompass these approaches, using tighter finite-size bounds than previous analyses. In doing so, we develop a method to compute tight lower bounds on the asymptotic keyrate for any such DIQKD protocol with binary inputs and outputs. With this, we show that positive asymptotic keyrates are achievable up to depolarizing noise values of 9.33%, exceeding all previously known noise thresholds. We also develop a modification to random-key-measurement protocols, using a pre-shared seed followed by a "seed recovery" step, which yields substantially higher net key generation rates by essentially removing the sifting factor. Some of our results may also improve the keyrates of device-independent randomness expansion.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 22, 2022
- Source ID
- 10.22331/q-2022-12-22-880
Entities
People
- Charles C.-w. Lim
- Ernest Y.-Z. Tan
- Jean-daniel Bancal
- Nicolas Sangouard
- Pavel Sekatski
- Renato Renner
- René Schwonnek
Organizations
- Air Force Office of Scientific Research
- Centre for Quantum Technologies
- ETH Zurich
- National Research Foundation
- Paris-Saclay University
- Swiss National Science Foundation
- University of Basel
- University of Geneva
- University of Siegen