基于接收信号随机特性的轻量级物理层密钥生成

In 5G emerging application scenarios, such as Internet of vehicles and Internet of things, communication nodes are densely distributed, dynamic migration and resource constrained. In order to satisfy the security requirements, it will face the problem of key distribution and lightweight encryption between mass communication nodes.. Physical layer key generation technology enables both parties to generate a time variant key by using the physical properties of the wireless channel. It provides a feasible way to solve the key distribution problem. However, there still exist the problem of low key generation rate and high computation cost.. In this research, we will take the space of received signals as a new random source and design a light-weight key generation method. In order to enlarge the key space and improve the key generation rate, transmitter will control the random, update time and strength of the key. Three aspects are studied in this research. Firstly, a key generation model is built based on the random properties of received signals. Security mechanism of key generation in this model will be researched. Secondly, we will design a series of slight-weight key generation method for the antenna asymmetric system. Thirdly, performance of the key generation method is analyzed when the received signals are affected by channel noise, as well as the optimization for the actual wireless environment.. The goal of our research is to overcome the security problem of physical layer in asymmetric transceiver resource system by providing a set of novel ideas and methods, which provide the theoretical basis as well as practical guidance for the field.

在以车联网、物联网为代表的5G新兴应用场景中，通信节点具有密集分布、动态迁移、资源受限等特点。为了满足节点间通信安全的需求，网络面临着与海量通信节点间的密钥分发和轻量级加密等难题。.物理层密钥生成技术借助无线信道的物理属性，使合法通信双方能够生成时变的密钥，为解决密钥分发难题提供了可行的途径。但仍存在密钥生成速率低和终端节点计算开销大等问题。.本课题将接收信号空间作为新的随机源，设计接收端轻量级的密钥生成方法，使密钥的随机性、更新时间和强度由发方主导，提高密钥生成速率。课题从以下三个方面展开研究：一是建立基于接收信号随机特性的密钥生成模型，对其安全机理开展研究；二是针对收发天线非对称系统，设计轻量级密钥生成方法；三是研究面向实际无线环境的密钥生成方法的安全性能分析以及优化方法。 .本课题的研究旨在为收发资源非对称系统的通信安全，提供一套新思路和新方法，为该领域发展提供理论基础和工程指导。

电磁波传播的开放性造成无线链路的脆弱性，通过无线信道窃取信息，利用漏洞发起无线接入攻击欺骗和致瘫网络等安全威胁日益突出，已成为无线通信安全的短板。本项目针对直接将经典的利用无线信道参数在物理层生成密钥的方法，照搬应用于收发天线非对称系统中，存在接收端信道估计复杂、密钥生成开销大，同时还要克服因信道变化缓慢导致所量化生成密钥更新速率低，安全性能下降的实际问题，本项目提出基于随机发送信号、随机发送方式叠加随机信道的多重随机密钥生成思路，并开展以下三方面研究：（1）基于接收信号随机特性的密钥生成模型与安全机理研。论证了从接收信号量化提取密钥的可行性，研究提出了最佳接收信号的概率分布，定量分析相对传统基于无线信道生成密钥方法的安全增量；（2）收发天线非对称系统中的轻量级密钥生成方法研究。建立了MISO/MIMO系统接收信号空间的物理层密钥生成模型，设计了由发端主导的密钥生成流程，接收端轻量级的密钥生成方案，提出了在不同信道参数统计分布下，发端生成随机数的最佳设计准则，提出了单向和双向信号随机性的密钥生成算法；（3）基于接收信号空间的密钥生成方法的安全性能分析。分析了信号发送方式、最佳采样位置、采样值的概率分布等环节对密钥生成速率的影响，以及影响合法通信双方密钥生成不一致概率、密钥容量等性能指标的关键参数。本项目在上述几个方面取得了一定的理论突破和技术创新，对促进无线内生安全方向发展起到了积极的推动作用。