【作者】 张阳；

【导师】 韩正甫； 郭光灿；

【作者基本信息】 中国科学技术大学 ， 光学， 2012， 博士

【摘要】 密码学一直在政治、军事、经济中扮演着重要的角色。保密通讯系统,最重要的一个基础就是密钥分配的安全性。传统的对称密码体制和非对称秘密体制主要基于计算复杂性。随着计算机的性能的不断提升,特别是未来量子计算机可能实用化,经典保密系统将面临严峻挑战。量子力学同样可以和密码学结合,来对抗可能的量子计算机。从1984年第一个量子密钥分配(QKD)协议提出,至今已近三十年的时间。包括量子密钥分配、量子秘密共享(QSS)等多种量子密码术被提出,并逐渐从理论转化为实验,开始了实用化的步伐。本文从实用性考虑,结合自己的研究主线,主要介绍光纤量子密码术的实验和实用化研究,包括QKD协议和实验的基本介绍,被动式诱骗态QKD的实验研究,QKD组网技术和实地测试以及QSS的实用扩展。本人的研究成果,主要体现在如下几个方面：1.被动式诱骗态量子密钥分配是很有用研究潜力的,特别是基于非线性器件的方案,比如M. Curty的方案(Optics Letters, Vol.34, p.3238,2009)。在实验上验证并改进了M. Curty的光源方案,完成了自稳定的非泊松光源,是实现被动式诱骗态QKD的关键器件。2.对M. Curty的方案(使用弱相干光源)在实际实验系统的拟合模型,提出修正。修正模型可以提供更好的模拟表现,也修订了最优化实验参数。结合非泊松光源和Faraday-Michelson量子密钥分配系统,完成了被动式诱骗态QKD的验证性实验,公共信道衰减可达22dB。3.作为主要成员,与研究组团队一起完成了北京四端口QKD网络,芜湖多层级QKD网络和芜湖五点QKD网络。三个实地实验,分别测试了利用量子路由器搭建全时全通网,多种组网技术的融合和分层设计,以及省波长的量子路由器。4.通过QKD网络实验,产生了QSS与QKD二者融合的想法,提出了非纠缠QSS扩展规模的实用模型。更多还原

【Abstract】 Cryptography plays an important role in politics, military and economics. The security of key distribution is the critical foundation of cryptosystem. Most of classical cryptosystems, including public key cryptosystem and symmetric key cryptosystem, are based on computation complexity. As the power of computation increases, the security of classical cryptosystems will have to face serous challenge, especially that the quantum computer may become practical in future.Combining quantum:mechanics and cryptography, we could protect the information against the quantum computer. It has been almost thirty years that the first protocol of quantum key distribution was proposed in1984. Several kinds of quantum cryptography were proposed, and verified in experiment and even practical applications.Fiber quantum cryptography is the subject in my research, which is more practical in experimental view. This paper will introduce point to point QKD protocols, passive decoy state QKD experiment, QKD network technology and field test, and idea about extending the quantum secret sharing in networks. The major results are listed as follows:1. Passive decoy state QKD has advantage in high speed application and security, especially those protocols based linear optical equipment, as the one proposed by M. Curty(Optics Letters, Vol.34, p.3238,2009). We proved the theory of the non-Poissonian light source in experiment, which is the most important part in the protocol, and proposed the intrinsic-stable structure.2. We modified Curty’s model using weak coherent light source for experiment. The modified model could offer better performance and renew the optimal parameters for experiments. And we also performed a proof-of-principle demonstration of passive decoy stat QKD over22.0dB channel loss, by combining the non-Poissonian light source and Faraday-Michelson system.3. We accomplished "Star Type" Metropolitan QKD Network in Beijing, robust hierarchical metropolitan QKD network and wavelength-saving QKD network in Wuhu. We tested the quantum router for the real-time full connectivity network, and built hierarchical networks. Moreover, A new scheme of quantum router was realized for wavelength-saving.4.From the experiment in QKD networks, we proposed a solution to expand the quantum secret sharing without entanglement in QKD networks.更多还原