Collective Noise Resistant Quantum Security Protocols Using GHZ States

• Main Authors: Chih-HungChang, 張智閎
• Other Authors: Tzonelih Hwang
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/27255392017385358880

碩士 === 國立成功大學 === 資訊工程學系 === 102 === Recently, the research in quantum computer and quantum algorithm is prospering due to the development of quantum mechanics. With quantum algorithm, the cryptosystems whose security is based on the problems of factorization and discrete logarithm can be bro-ken with polynomial time. As development on quantum computer area keeps maturing, se-curity technique based on modern cryptography will face a sever threat. In this regard, Quantum cryptography is a novel area coming after quantum physics and cryptography. Different from the modern cryptography that is designed on the basis of intricate calcula-tion and intractable mathematical problems, quantum cryptography can be utilized to de-sign security protocols according to the property of quantum physics. In recent years, research about quantum key distribution, quantum communication has been the focus in the area of quantum cryptography, and the research is applied to many areas including quantum key distribution, quantum key agreement, probabilistic quantum key distribution, quantum secure direct communication, deterministic secure quantum communication, quantum dialogue, quantum secret sharing, quantum private comparision and quantum signature are widely studied. Nevertheless, most of existing quantum protocols are arranged under the assumption that quantum channel is an ideal channel. In other words, a quantum channel is not affected by any noise while the photons are transmitted through the quantum channel. However, in realilty, two legitimate communicants need to transmit photons through optical fiber. But during the transmission process, the collective noise is generated because of the fluctuation of the birefringence in optical fiber. If the quantum channel is not assumed to be ideal, it is difficult to discern between mistakes caused by the collective noise and mistakes caused by malicious eavesdropper when the eavesdropper checking process are performed in the quantum protocols. Aiming to exploit this weak point, an eavesdropper is able to cover its attack by this kind of noise, which misleads legitimate communicants into believing that mistakes are caused by the noise during their public discussion procedure. As a result, how to design a secure quantum protocol under the condition that quantum channel is disturbed by the collective noise is being the most widely discussed issue in quantum cryptography. This thesis focuses on designing secure quantum protocols based on the proposed coding methods by using the GHZ states and the GHZ-like states in order to repel the col-lective noise. The purpose of this thesis is providing a way to improve security of quantum protocols under the condition that the quantum channel suffers from the collective noise. Here, the quantum protocols include probabilistic quantum key distribution, quantum pri-vate comparision and quantum dialogue.