Eavesdropping of two-way coherent-state quantum cryptography via Gaussian quantum cloning machines

Abstract

We consider one of the quantum key distribution protocols recently introduced in Ref. [Pirandola et al., Nature Physics 4, 726 (2008)]. This protocol consists in a two-way quantum communication between Alice and Bob, where Alice encodes secret information via a random phase-space displacement of a coherent state. In particular, we study its security against a specific class of individual attacks which are based on combinations of Gaussian quantum cloning machines.

Proceeding of ICQNM 2009, The Third International Conference on Quantum, Nano and Micro Technologies, Cancun, Mexico, 1-7 February 2009