2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/220643We 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 2009Quantum Physicstext