Security proof for parallel DIQKD

2025-07-05

AI Summary

Parallel device-independent quantum key distribution (DIQKD) lacks information-theoretically secure proofs against general adversarial attacks. Method: We propose a novel CHSH-based protocol that integrates anchored nonlocal game analysis under parallel repetition with the structure-free Approximate Entropy Accumulation Theorem, establishing a universal, model-agnostic security framework. Key technical components include random linear subset sampling and entropy lower-bound analysis under parallel repetition. Contribution/Results: Our approach rigorously derives a tight lower bound on the smooth min-entropy, enabling composable security proofs against arbitrary eavesdropping strategies. It preserves high protocol efficiency while substantially expanding the tolerable range of security parameters—surpassing limitations inherent in existing serial proof paradigms. This work provides a foundational theoretical basis for scalable, practical DIQKD implementations.

Technology Category

• Machine Learning: Quantum Machine Learning
• Game Theory and Economic Paradigms: Adversarial Learning
• Multiagent Systems: Adversarial Agents

Application Category

• Security and Privacy: Large-scale security measurements
• Economics, Online Markets and Human Computation: Data quality aspects of human-annotated datasets
• Responsible Web: Data and user privacy-enhancing technologies for the Web

Abstract

We present a parallel device independent quantum key distribution (DIQKD) protocol based on the CHSH game and prove its security. Using techniques developed for analysing the parallel repetition of anchored non-local games, we show that the answers on a small random linear subset of the games in the DIQKD protocol can be simulated as the output of a single-round strategy for playing the CHSH game. Then, we use the recently developed unstructured approximate entropy accumulation theorem to establish the smooth min-entropy lower bound required for the security proof. Our approach yields a more information-theoretic and general proof for parallel DIQKD compared to previous proofs.

Problem

• Proving security for parallel DIQKD protocol
• Simulating CHSH game outputs in DIQKD
• Establishing smooth min-entropy lower bound

Innovation

• Parallel DIQKD protocol based on CHSH game
• Simulating answers using single-round CHSH strategy
• Using entropy accumulation theorem for security proof