Simulating Secure Key Distribution over Quantum Satellite Channel
Andras Kiss, Laszlo Bacsardi
Institute of Informatics and Economics
University of West Hungary
In this work, we have dealt with the examination of the laser-based space communications over quantum channel. This is one of the most promising communication technique if we consider the advantages of the quantum communication in further opportunities. According to the quantum computation laws, an unknown quantum bit cannot be copied perfectly and this fact makes safe data transmission even in case of an eavesdropping attack.
The base unit of the quantum computing is the quantum bit (qubit), which can be represented by different polarization states of a photon. The state of a classical bit can be represented by only one of the 0 and 1 values, but the qubit can be an in arbitrary superposition of 0 and 1. There are two groups of the currently used quantum key distribution (QKD) solutions. The first generation protocols use singe-photon sources, while coherent laser is used and the wave properties of light is exploited in the second generation protocols. This first approach is named as Discrete Variable QKD (DV-QKD), the second one is named as Continuous Variable QKD (CV-QKD).
To analyze a quantum communication channel with laser sources, we have to take into account several physical parameters. To complete the determination of the Quantum Bit Error Rate of a DVQKD protocol, a series of derived procedures are needed to execute, which has high complexity.
The development of a simulation software was also part of our work, which issues all of the interpretable information about the properties of the communication channel. This is a desktop application written in Java language. The implemented six scenarios are the following: Calculating by constant parameters, Calculating by varying parameters, Sensitivity analysis, Time driven communication, Optimization, Channel analysis. Simulations can be run almost on every communication channel type—including Earth-space, space-Earth and space-space channels—and channel length, but in this paper we focused on Earth-LEO (Low Earth Orbit) and LEO-Earth channels. In practical usage of laser communication, our work covers the examination of key distribution procedure by BB84, B92, S09 and Gisin quantum key distribution protocols.
The research was supported by the Hungarian Scientific Research Fund – OTKA PD-112529.