Research On And Implementation Of Data Reconcili-ation Protocol In Quantum Key Distribution System

Quantum communication, a new cross-disciplinary developed in the last two decades, is a new research field which combines quantum theory with communication theory. Information transfer can be implemented with unconditional security and high efficiency by using the basic principles of quantum physics. At present, the quantum communication is mainly related to: quantum cryptography communication based on quantum key distribution, quantum teleportation, quantum dense coding and quantum secure direct communication, etc. In recent years, the quantum cryptography communication has been gradually developing to practicality, in which data reconciliation is one of the key technologies.Firstly, the basic theory of quantum cryptography communication is introduced, and the scheme and brief performance analysis of quantum key distribution system based on BB84 protocol is presented. The platform on which this dissertation is based is also introduced.Secondly, the advantages and disadvantages of binary correcting protocol, cascade reconciliation protocol, Hamming code based reconciliation protocol are analyzed by the designed software. The principle and implementation of the privacy amplification is also presented.Thirdly, a new method of data reconciliation based on Low-Density Parity-Check (LDPC) code is suggested. In which quantum bit error rate and Back Relief Propagation method are applied to process the sifted key, and the right codes are estimated by using the maximum a posteriori probability (MAP) decoding. Test results show that the safety and efficiency of the data reconciliation is improved.Finally, the summary of the whole dissertation and the prospects for the next step are put forward.