Secret key distillation across a quantum wiretap channel under restricted eavesdropping

Abstract

The theory of quantum cryptography aims to guarantee unconditional information-theoretic security against an omnipotent eavesdropper. In many practical scenarios, however, the assumption of an all-powerful adversary is excessive and can be relaxed considerably. In this paper we study secret key distillation across a lossy and noisy quantum wiretap channel between Alice and Bob, with a separately parameterized realistically lossy quantum channel to the eavesdropper Eve. We show that under such restricted eavesdropping, the key rates achievable can exceed the secret key distillation capacity against an unrestricted eavesdropper in the quantum wiretap channel. Further, we show upper bounds on the key rates based on the relative entropy of entanglement. This simple restricted eavesdropping model is widely applicable, e.g., to free-space quantum optical communication, where realistic collection of light by Eve is limited by the finite size of her optical aperture. Future work will include calculating bounds on the amount of light Eve can collect under various realistic scenarios.

arXiv comment14 pages, 19 figures. We welcome comments and suggestions

References in corpus (22)

• Separability Criterion for Density Matrices
• The Security of Practical Quantum Key Distribution
• Gaussian Quantum Information
• Separability of Mixed States: Necessary and Sufficient Conditions
• Decoy State Quantum Key Distribution
• Peres-Horodecki separability criterion for continuous variable systems
• General Benchmarks for Quantum Repeaters
• Fundamental Limits of Repeaterless Quantum Communications
• Quantum data processing and error correction
• A de Finetti representation theorem for infinite dimensional quantum systems and applications to quantum cryptography
• Continuous-Variable Quantum Key Distribution with Gaussian Modulation -- The Theory of Practical Implementations
• Distributing Secret Keys with Quantum Continuous Variables: Principle, Security and Implementations
• Direct and Reverse Secret-Key Capacities of a Quantum Channel
• Gaussian measures of entanglement versus negativities: the ordering of two-mode Gaussian states
• Converse bounds for private communication over quantum channels
• Reverse Coherent Information
• Strong converse rates for quantum communication
• Gaussian entanglement revisited
• Unified approach to quantum capacities: towards quantum noisy coding theorem
• Hacking Quantum Key Distribution via Injection Locking
• Unconstrained Capacities of Quantum Key Distribution and Entanglement Distillation for Pure-Loss Bosonic Broadcast Channels
• Optimal realistic attacks in continuous-variable quantum key distribution

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• Quantum Keyless Private Communication with Decoy States for Space Channels
• Assessing a binary quantum channel exploiting a Silicon photomultiplier based hybrid receiver
• Quantum communications in continuous variable systems