Security of the decoy state method for quantum key distribution
Abstract
Quantum cryptography or, more precisely, quantum key distribution (QKD), is one of the advanced areas in the field of quantum technologies. The confidentiality of keys distributed with the use of QKD protocols is guaranteed by the fundamental laws of quantum mechanics. This paper is devoted to the decoy state method, a countermeasure against vulnerabilities caused by the use of coherent states of light for QKD protocols whose security is proved under the assumption of singlephoton states. We give a formal security proof of the decoy state method against all possible attacks. We compare two widely known attacks on multiphoton pulses: photonnumber splitting and beam splitting. Finally, we discuss the equivalence of polarization and phase coding.
 Publication:

Physics Uspekhi
 Pub Date:
 January 2021
 DOI:
 10.3367/UFNe.2020.11.038882
 arXiv:
 arXiv:2101.10128
 Bibcode:
 2021PhyU...64...88T
 Keywords:

 quantum cryptography;
 quantum key distribution;
 BB84;
 decoy states;
 03.67.  a;
 03.67.Dd;
 03.67.Hk;
 Quantum Physics
 EPrint:
 18 pages, 1 figure