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.

Corrected error in Chernoff bound formula

References in corpus (8)

• Distillation of secret key and entanglement from quantum states
• Device-independent quantum key distribution secure against collective attacks
• Grothendieck's constant and local models for noisy entangled quantum states
• Noisy pre-processing facilitating a photonic realisation of device-independent quantum key distribution
• Device-independent quantum key distribution with random postselection
• Cryptographic security of quantum key distribution
• Computing conditional entropies for quantum correlations
• Device-independent quantum key distribution from generalized CHSH inequalities

Cited by in corpus (11)

• Experimental device-independent quantum key distribution between distant users
• Security of device-independent quantum key distribution protocols: a review
• Security of quantum key distribution from generalised entropy accumulation
• Quantum Correlations in the Minimal Scenario
• Boosting device-independent cryptography with tripartite nonlocality
• Experimental quantum key distribution certified by Bell's theorem
• Device Independent Quantum Key Distribution with realistic single-photon source implementations
• Improved device-independent randomness expansion rates using two sided randomness
• Security of differential phase shift QKD from relativistic principles
• Upper bounds on key rates in device-independent quantum key distribution based on convex-combination attacks
• Quantum Chernoff divergence in advantage distillation for quantum key distribution and device-independent quantum key distribution