Security against individual attacks for realistic quantum key distribution

Abstract

I prove the security of quantum key distribution against individual attacks for realistic signals sources, including weak coherent pulses and downconversion sources. The proof applies to the BB84 protocol with the standard detection scheme (no strong reference pulse). I obtain a formula for the secure bit rate per time slot of an experimental setup which can be used to optimize the performance of existing schemes for the considered scenario.

On‐chip single photon sources using planar photonic crystals and single quantum dots

“…The easiest and most straightforward way is to attenuate pulsed lasers [5], though in this case the production of single photons is probabilistic. Therefore, there may be no photons, several photons, or many photons, since the photon number generated is subject to Poissonian statistics; this can be problematic for a number of applications such as quantum cryptography because of possible photon number-splitting attacks ("eavesdropping") [6,7]. Another more practical approach for obtaining single photons is to exploit spontaneous parametric down conversion in nonlinear crystals [8], where higher-frequency pump photons incident on a nonlinear crystal are occasionally split into a pair of lower-frequency photons; one of these photons (the "heralding" photon) is used to herald the arrival of the second photon ("heralded" photon), and thus the second photon can be well isolated and manipulated.…”

Quantum Key Distribution

“…Key words here are squashing models (Lütkenhaus (2000)) and device-independent protocols (Masanes et al (2011)). Squashing models allow the use of qubit-based security proofs for non-qubit-based implementations.…”

Performance of various quantum-key-distribution systems using1.55‐μmup-conversion single-photon detectors

“…The most common QKD protocols, which have been implemented in experiments over the last years [1], are the BB84 protocol, which uses single photons as information carriers [2], and the entanglement-based BBM92 protocol [3]. A security analysis for these protocols under realistic system parameters and against individual attacks has been performed [4,5]. This analysis shows that the performance of a quantum cryptography system, in terms of communication distance and secure communication rate, is determined by the characteristics of the source of single or entangled photons, and of the single-photon detectors.…”