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arXiv · 1501.07212

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

Cosmo Lupo·Seth Lloyd
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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.

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Cosmo Lupo, Seth Lloyd. 2015-10-12. Continuous-variable quantum enigma machines for long-distance key distribution. https://doi.org/10.1103/physreva.92.062312

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