Quantum-locked key distribution at nearly the classical capacity rate

Abstract

Quantum data locking is a protocol that allows for a small secret key to (un)lock an exponentially larger amount of information, hence yielding the strongest violation of the classical one-time pad encryption in the quantum setting. This violation mirrors a large gap existing between two security criteria for quantum cryptography quantified by two entropic quantities: the Holevo information and the accessible information. We show that the latter becomes a sensible security criterion if an upper bound on the coherence time of the eavesdropper's quantum memory is known. Under this condition we introduce a protocol for secret key generation through a memoryless qudit channel. For channels with enough symmetry, such as the d-dimensional erasure and depolarizing channels, this protocol allows secret key generation at an asymptotic rate as high as the classical capacity minus one bit.

arXiv commentv2 is close to the published version and contains only the key distribution protocols (4+5 pages), an extended version of the direct communication protocol is posted in arXiv:1410.4748 Comments always welcome

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Cited by in corpus (16)

• Advances in Quantum Cryptography
• A Quantum Enigma Machine: Experimentally Demonstrating Quantum Data Locking
• Superadditivity of private information for any number of uses of the channel
• Experimental quantum data locking
• Quantum cryptography beyond key distribution: theory and experiment
• Optimal realistic attacks in continuous-variable quantum key distribution
• Quantum data locking for high-rate private communication
• Continuous-variable quantum enigma machines for long-distance key distribution
• Quantum data hiding in the presence of noise
• Photonic quantum data locking
• Metric and classical fidelity uncertainty relations for random unitary matrices
• Fault tolerant quantum data locking
• Hybrid Quantum Cryptography from Communication Complexity
• Maximal Holevo quantity based on weak measurements
• Characterizing High-Dimensional Optical Systems with Applications in Compressive Sensing and Quantum Data Locking
• One-Way Deficit and Holevo Quantity of Generalized $n$-qubit Werner State