Continuous-variable quantum enigma machines for long-distance key distribution

Abstract

Quantum physics allows for unconditionally secure communication through insecure communication channels. The achievable rates of quantum-secured communication are fundamentally limited by the laws of quantum physics and in particular by the properties of entanglement. For a lossy communication line, this implies that the secret-key generation rate vanishes at least exponentially with the communication distance. We show that this fundamental limitation can be violated in a realistic scenario where the eavesdropper can store quantum information for only a finite, yet arbitrarily long, time. We consider communication through a lossy bononic channel (modeling linear loss in optical fibers) and we show that it is in principle possible to achieve a constant rate of key generation of one bit per optical mode over arbitrarily long communication distances.

13 pages. V2: new title, new result on active attacks, increased rigour in the security proof

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Cited by in corpus (6)

• Advances in Quantum Cryptography
• A Quantum Enigma Machine: Experimentally Demonstrating Quantum Data Locking
• Optimal realistic attacks in continuous-variable quantum key distribution
• Quantum data hiding in the presence of noise
• Fault tolerant quantum data locking
• Hybrid Quantum Cryptography from Communication Complexity