A simple proof that Gaussian attacks are optimal among collective attacks against continuous-variable quantum key distribution with a Gaussian modulation

Anthony Leverrier (1, 2) , Philippe Grangier (2)

1 LTCI - Laboratoire Traitement et Communication de l'Information
2 Laboratoire Charles Fabry de l'Institut d'Optique / Optique quantique

In this paper, we give a simple proof of the fact that the optimal collective attacks against continous-variable quantum key distribution with a Gaussian modulation are Gaussian attacks. Our proof makes use of symmetry properties of the quantum key distribution protocol in phase-space.

Domains: Quantum Physics [quant-ph]

Anthony Leverrier, Philippe Grangier. A simple proof that Gaussian attacks are optimal among collective attacks against continuous-variable quantum key distribution with a Gaussian modulation. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2010, 81, pp.062314. ⟨10.1103/PhysRevA.81.062314⟩. ⟨hal-00553558⟩