基于无周期混沌同步动态键控的高速密钥安全分发研究

One-time pad is absolutely secure communication, but high-speed secure key distribution is the bottleneck of its practical application. The unconditionally secure quantum key distribution (QKD) has made important progress, but long-distance QKD still needs to solve the difficulty of low distribution rate. By contrast, key distribution based on correlated randomness of wideband chaotic laser has the potential of greatly improving distribution rate, but the defects of exchanging and comparing modulating keys on public channel and divulging external-cavity length of chaotic system reduce its security. .In this project, we propose to construct non-period chaos synchronization by using two mutually coupled semiconductor lasers subject to dispersive optical feedback from chirped fiber Bragg gratings (CFBGs), which avoids divulging the information of external-cavity length of chaotic system. Furthermore, combining with the modulation of high-speed keys, the dynamic keying of chaos synchronization can be realized. According to the synchronization state on public channel and its own modulating keys, legitimate users are capable of inferring modulating keys of the other party, which enables sharing keys while avoiding the exchange and comparison of modulating keys. In this project, the dynamical characteristics of two mutually coupled semiconductor lasers subject to dispersive optical feedback from CFBGs are investigated, by which the conditions of non-period chaos generation, non-period chaos synchronization as well as its dynamic keying for realizing key distribution are obtained. Finally, the experimental verification system of point-to-point key distribution is established..Beyond the QKD, this project will provide a new idea of physical entropy source-based high-speed secure key distribution, which enriches the existing schemes of key distribution.

“一次一密”是绝对安全的保密通信，但高速密钥安全分发是其应用瓶颈。无条件安全的量子密钥分发已取得重要进展，但长距离量子密钥分发尚存在分发速率低的技术难点。基于宽带混沌激光相关随机性的密钥分发具有显著提高分发速率的潜力，但调制密钥通过公共信道交换对比以及混沌系统外腔长度信息泄露导致其安全性不足。.本项目提出利用互耦合啁啾光纤光栅反馈半导体激光器构建无周期混沌同步系统，避免系统外腔长度信息泄露；结合高速密钥调制实现混沌同步动态键控，合法用户根据公共信道混沌同步状态及己方调制密钥推断对方调制密钥，无需交换对比便可实现密钥共享。项目将研究互耦合啁啾光纤光栅反馈半导体激光器动力学特性，探明无周期混沌激光产生条件，揭示无周期混沌同步及其动态键控实现密钥分发的条件和机理，最终建立点对点密钥分发实验验证系统。.本研究将在量子密钥分发之外提供一个基于物理熵源的高速密钥安全分发新思路，丰富现有密钥分发方案。

混沌激光具有大带宽、高随机、可同步等特性，在高速物理密钥分发领域具有重要应用潜力。镜面反馈半导体激光器因结构简单、易于操作而成为混沌激光的首选光源。但是，由于镜面线性反馈结构具有外腔谐振，其产生的混沌信号蕴含弱周期性，限制了密钥分发的安全性。.本项目提出利用无周期混沌同步键控实现高速密钥安全分发。我们按原定计划开展了研究，并取得了预期成果：构建了啁啾光纤光栅（CFBG）反馈半导体激光器理论模型，探明了无周期混沌的产生机理与参数条件；实验实现了高质量的无周期混沌同步，从同步混沌中提取了2.5Gb/s相关裸钥；提出了基于CFBG色散键控混沌同步、激光器模式键控混沌同步的密钥分发方案，实现了距离超百公里、速率Gb/s量级的高速密钥安全分发。.项目执行过程中，取得了如下主要成果：在Light Sci Appl(Nature子刊)、Opt Lett、Opt Express、IEEE J Quantum Electron、IEEE Photon Technol Lett等本领域权威期刊发表论文14篇；申请发明专利13项，其中，已授权9项（含1项美国专利）；获全国半导体光源系统创新竞赛优秀奖1项；参加国内外学术合作交流17人次；培养硕士研究生2人；项目负责人入选山西省“三晋英才”支持计划青年优秀人才。.本项目在量子密钥分发之外探索了一种基于物理熵源的高速密钥安全分发新方案，丰富了现有密钥分发理论与关键技术，助力于解决高速信息物理安全传输难题。