The Research On The Key Technology Of Differential Phase Shift Quantum Key Distribution

With the rapid development of information science and technology, the quantity ofinformation grows quickly, so does the need of cryptographic key in encryptioncommunication system. The traditional encryption schemes which depend oncomputational complexity can’t meet the increasing need gradually. At the same time,the quantum computer seriously endangers the RSA public key scheme all the time. Asa dependable key scheme, the quantum key distribution (QKD) could acquireunconditional security theoretically. An encryption communication system couldachieve absolute security by combining QKD with one-time-pad Vernam encryption.Among numerous QKD protocol, the differential phase shift quantum key distribution(DPS-QKD) attracts extensive attention owing to its practical architecture, higher keyefficiency, and longer communication distance.Firstly, the research significance and purpose of QKD system were discussedthrough the investigation of relevant literature. The evolution of QKD and fundamentalprinciple of quantum mechanics were introduced respectively. Then the threemainstream protocols in QKD—BB84, E91and B92were discussed later in the aspectsof theory, architecture and efficiency. Particularly, we discussed the theory, architectureand security of the DPS-QKD scheme. By researching the crucial instruments of DPS-QKD system one by one, we designed data acquisitioning module, and accomplished allfunction modules by Verilog hardware discription language. Finally, a DPS-QKDsystem which could distribute quantum key was constructed.All the possible eavesdropping aimed at DPS-QKD system and correspondingdefensive strategies were discussed and analyzed. According to research of security,DPS-QKD scheme could defense the photon number splitting eavesdropping moreeffectively than the BB84-QKD scheme. Finally, two proposals for improvement aboutthe weak coherent light source and single photon detector were presented.