【作者】 蒙积林；

【导师】 龙桂鲁；

【作者基本信息】 清华大学 ， 粒子物理与原子核物理， 2003， 硕士

【摘要】 密码学主要是研究通信安全保密的学科。量子密码学是密码学与量子力学结合的产物, 利用量子不可克隆定理和海森堡测不准原理等量子特性，量子密码通信理论上已经证明是绝对安全。量子密码通信在密钥分发上的实验已经得到巨大进展，预计很快能投入应用，在军事、电子银行保密等方面将有广泛的应用前景。本论文先介绍经典密码学的发展，接着比较详细地介绍了量子密码通信的原理，然后结合我们在自由空间中B92量子密钥分发的演示实验，详细介绍了我们自行研制的演示实验电子控制系统。该控制系统主要包括控制单光子发射、单光子探测器、数据采集接收系统的输出系统和数据采集系统两个模块，它们都采用复杂可编程逻辑器件CPLD作为核心功能芯片，由硬件电路设计、芯片编程和高级软件编程三部分组成。其硬件电路由专业软件设计出原理图SCH和印刷电路图PCB生成，再GERBER文件，然后光绘而成，CPLD芯片编程（采用硬件描述语言Verilog HDL）经过设计、模拟、装配、下载完成，高级软件编程采用C语言I/O方式利用ISA总线接口与外设进行通信。输出系统能控制单光子发射时间在50ns到3.2ms之间步进50ns可调，发射频率在500Hz到100kHz之间步进1Hz可调，并能很好地控制单光子探测器和数据采集系统的工作。由于系统是采用软核做芯片，所以系统功能能随着应用需求灵活变动，使系统集成量子通讯算法在单一芯片上成为可能。更多还原

【Abstract】 Cryptography is the subject study of the secure communication. Quantum cryptography(QC) is the combination of classical cryptography and quantum mechanics. The characteristics of quantum mechanics, such as no-cloning theorem and Heisenberg’s uncertainty principle, provide the perfect secrecy for quantum cryptographic communication. Being the first application of quantum physics, quantum key distribution(QKD) has been developed very fast experimentally in recent years. It would impact thoroughly the existing secure communication, especially in military affairs, e-banking and so on.In this paper, the principle of the QKD was discussed in detail together with an the introduction of classical cryptographic communication. Then we present description of our QKD experiment setup based on B92 protocal. The paper is focused on the control system of our QKD apparatus.The control system includes two modules, one named the input module which acquires data digitally, and the other, named the output module, controls the emission of the laser, the gating function of the single photon counting module(SPCM) and the synchronization of the input and output modules. Each of them uses a complex programmable logic device(CPLD) as the core component, and is devided into three parts: the hardware circuit, the programming logic circuit and the software. The hardware circuit boards are produced by a laser photoplotter according to the Gerber files gererated from the schematic(SCH) documents and the printed circuit board(PCB) documents. The CPLDs, programmed with the Verilog Hardware Description Language (Verilog HDL), were completed after four steps: design, simulation, synthesis and fit. The software is developed with C language using direct I/O to communicate with the device through the ISA bus computer interface. The output module can set the interval of the laser pulse to change from 50ns to <WP=5>3.2ms in steps of 50ns, and the frequency from 500Hz to 100kHz in steps of 1Hz. It can control well the SPCM and the input module. Because of the embeded soft core, the function of the control system can change with varying demands of the application. That makes it possible to integrate the quantum communication algorithm into one chip.更多还原