基于细粒度极化的隐蔽密钥分发方案  

Covert Secret-Key Distribution Scheme Based on Fine-Grained Polarization

作　　者：徐明[1,2] 吴佳佳 XU Ming;WU Jia-Jia(College of Information Engineering,Shanghai Maritime University,Shanghai 201306;College of Electronics and Information Engineering,Tongji University,Shanghai 201804)

机构地区：[1]上海海事大学信息工程学院,上海201306 [2]同济大学电子与信息工程学院,上海201804

出　　处：《计算机学报》2023年第1期147-162,共16页Chinese Journal of Computers

基　　金：国家自然科学基金面上项目(62172269);中国博士后科学基金项目(2014M561512)资助.

摘　　要：针对现有密钥分发协议在水声信道环境下的信息泄露问题,提出了一种基于细粒度极化的隐蔽密钥分发(Covert Secret-key distribution based on Fine-grained Polarization,CSFP)方案.首先,采用一致最大功效检验方法建立敌手模型,并给出隐蔽密钥分发方案的形式化定义.考虑到水声信道的非对称性和衰落效应,根据注水原理推导出信息传输速率达到香农极限时最优码字符号分布对应的带宽以及信道容量,并利用莱布尼兹积分法则和黎曼积分的保号性推导出信道容量与信道增益的函数关系,通过计算水声信道增益对极化子信道的容量进行排序实现极化码的码字构造,确保信息传输速率达到香农极限.其次,对信息比特索引集合进行细粒度极化,采用链式结构将多个消息块依次链接实现信息比特索引序列的对齐,设计出多轮通信下隐蔽密钥分发的编码和解码算法,利用合法发送方和接收方共享的随机种子对首轮传输的消息块进行初始化,并从当前生成的密钥中提取出随机种子对后续消息块进行随机化,确保密钥分发过程的隐蔽性.最后,通过信息理论证明了CSFP方案的可靠性、随机性、保密性和隐蔽性,利用最大熵原理推导出水声信道环境下隐蔽性约束的可达性条件和隐蔽密钥生成速率.仿真结果表明,与现有方案相比,CSFP方案的隐蔽密钥生成速率平均提高了18.78%,隐蔽概率平均提高了38.29%.此外,CSFP方案生成的密钥成功通过了SP 800-22测试平台的随机性检测.Underwater acoustic communication is increasingly being perceived as a promising means for marine life monitoring,ocean exploration,underwater navigation and surveillance.In order to defend against the potential security threats,two legitimate parties in the communication adopt key distribution protocols to negotiate a secret-key to encrypt the transmitted data.However,the characteristics of the underwater acoustic channel(UAC)and its inherent vulnerability make the communication process of secret-key distribution protocols easy to be detected,rendering the inevitable information leakage.Some researchers have introduced covert communication into secret-key distribution protocols to keep them undetectable by a warden based on random codes,and have even extended the ideas of covert communication to quantum key distribution.However,achieving information theoretical security with practical coding schemes is of definite interest.To this end,some covert secret-key distribution protocols based on polar codes are proposed for symmetric channels with uniformly distributed binary sequences.In these scenarios,the legitimate users aim at extracting a common secret-key from their observations through public communications.However,it is not feasible to apply polar codes directly to the UAC since the Bhattacharyya parameters of polarized channels cannot be calculated and sorted over asymmetric channels.To address these problems,a Covert Secret-key distribution scheme based on Fine-grained Polarization(CSFP)is proposed under the environment of UAC.First,a uniformly most powerful test is adopted to build the adversary model,and the formal definition of covert secret-key distribution scheme is given.Considering the asymmetry and fading effects of the UAC,the bandwidth and the channel capacity corresponding to the optimum symbol distributions of codewords are derived by the water-filling principle for the information transmission rate to achieve the Shannon limit theoretically,and the functional dependence between channel capacity

关 键 词：水声信道 信息泄露 细粒度极化 信道增益 隐蔽密钥分发 

分 类 号：TP309[自动化与计算机技术—计算机系统结构]