标准模型下高效的基于口令认证密钥协商协议

基于口令的认证密钥协商协议是利用预先共享的口令协商安全性较高的密钥。现有的基于口令认证密钥协商协议大多需要较大的计算量,或者只在随机预言模型下证明了协议的安全性。该文提出了新的标准模型下基于口令密钥协商协议,协议只需要一个生成元。 与其它标准模型下的协议相比,新协议不需要CPA或CCA2安全的加密方案,因而具有计算复杂度低和协议描述简单的特点。相对于殷胤等人在标准模型下可证安全的加密密钥协商协议一文中提出的协议,新协议将指数运算降低了64%。最后,基于DDH假设,在标准模型下证明了协议的安全性。     

基于LWE的集合相交和相等的两方保密计算

利用格上LWE (Leaning With Error)困难性假设,将保密地比较两个数是否相等转化为判断对随机串加密后的解密是否正确,有效地解决了数和集合关系的判定、求集合交集和集合相等安全多方计算问题,并利用模拟范例证明该协议在半诚实模型下是安全的。与传统的基于数论的协议相比,该方案由于不需要模指数运算,因而具有较低的计算复杂度,同时因其基于格中困难问题,因而能抵抗量子攻击。     

一种具有可扩展性的RFID标签轻量级组证明协议

组证明(Grouping-proof)协议的目的是证明阅读器扫描范围内待扫描标签组内标签是否同时存在。随着标签组和组内标签数量的增长,协议中存在的计算时间复杂度、通信总量、组证明生成机制和标签干扰等制约扩展性的因素严重影响了生成有效组证明的成功率。通过比较分析相关协议,设计了一个适用于大规模标签组的只需简单异或和伪随机运算的轻量级组证明协议。在相同的假设模型下,协议能抵抗常见安全攻击,满足强隐私特性的同时,符合超高频段低成本被动式标签的硬件成本要求,具有更高的执行效率。     

无双线性对的基于身份的认证密钥协商协议

鉴于目前大多数基于身份的认证密钥协商(ID-AK)协议需要复杂的双线性对运算,该文利用椭圆曲线加法群构造了一个无双线性对的ID-AK协议。协议去除了双线性对运算,效率比已有协议提高了至少33.3%;同时满足主密钥前向保密性、完善前向保密性和抗密钥泄露伪装。在随机预言机模型下,协议的安全性可规约到标准的计算性Diffie-Hellman假设。     

基于椭圆曲线的三方比特承诺

比特承诺是安全多方计算中最重要的基础协议之一,对构建更复杂的多方协议起着重要作用。该文提出了三方比特承诺模型,在该模型中,由两个证明者共同向一个验证者作出承诺。给出了基于椭圆曲线的三方比特承诺方案,经证明,尽管该方案完全基于经典计算环境,但是并不需要对协议参与方的计算能力作任何限制性假设,具有无条件安全性且对信道窃听免疫。该方案同时可以推广到比特串承诺协议。     

安全的认证密钥协商协议研究

对基于证书的密钥协商协议的设计与分析进行了比较深入的研究,研究内容包括：可证明安全的基于证书的密钥协商协议以及一种新的可认证密钥协商协议。主要研究成果有：介绍了密钥协商协议的概念和安全特性;提出一个新的认证密钥交换协议AKE-1。AKE-1效率较高,并且在最新的eCK07模型下是安全的,证明基于随机预言假设和CDH假设。另外,基于AKE-1,提出一轮的变体（满足只有一个实体在线）和三轮的变体（提供密钥确认属性）,以满足不同的应用。     

基于云仿真平台的医院HIS系统数据安全多方计算协议

考虑到传统协议在医院HIS系统中存在丢包率高、运行时间长和计算复杂度高的问题,提出了基于云仿真平台的医院HIS系统数据安全多方计算协议。利用云仿真平台,从风险等级和风险概率等方面,评估了医院HIS系统数据的安全风险;根据医院HIS系统数据安全信息的属性取值,优化了医院HIS系统数据的分类属性;结合医院HIS系统数据安全信息的提取模型,设计医院HIS系统数据安全多方计算协议。实验结果表明,该方法可以降低丢包率、缩短运行时间并降低计算复杂度,保证了医院HIS系统中数据的安全性。     

UC安全的高效不经意传输协议

非承诺加密机制是语义安全的,不能抵抗选择密文攻击.在non-erase模型的安全假设下,基于非承诺加密机制的不经意传输协议不能实现自适应攻击者UC(Universally Composable)安全的定义.利用可否认加密体制和可验证平滑投影哈希函数,提出了一个新的不经意传输协议,可否认加密体制通过陷门承诺的双陷门解密技术实现,新协议方案是可证明UC安全的,基于公共参考串模型,安全性可以归约为确定性复合剩余假设.新协议参与方能够处理指数空间的消息,计算效率得到改善,通过两次协议交互可以实现string-OT协议,与bit-OT协议相比单轮通信效率提高O(n)倍.     

基于知识的协议验证方法

协议验证是一个时空耗费很高的问题，本文将人工智能技术引入协议验证，建立了验证的图搜索模型，定义了协议错误、协议正确程度、验证算法的复杂度等概念。本文还提出了一个基于知识的协议验证算法Ｚ，并分析了其复杂度。     

广义可能性计算树逻辑的模型检测问题

本文首先分别给出了"约束可达","总是可达"这两个公式在广义可能性计算树逻辑（GPoCTL）中的另外两种等价形式;其次讨论了基于广义可能性测度的计算树逻辑的模型检测问题,将GPoCTL的模型检测问题规约为经典的CTL模型检测问题,利用截集的方法,给出了计算GPoCTL的模型检测问题的算法及其复杂度,并通过实例分析说明了这种算法的可行性;最后,研究了具有公平性假设的GPoCTL模型检测问题的计算复杂度,得到了与上面相似的结论.     

基于RED的AODV路由协议改进

基于当前使用非常广泛的随机早期检测（RED）拥塞控制机制，提出了一种改进方案：在AODV的路由发现阶段，根据当前平均队列长度来确定以不同的方式响应路由请求，从而使建立起来的路由比较可靠，使数据流可以绕过负担比较重的节点，实现一定程度的拥塞控制和流量均衡，最后对改进前后的协议进行了性能仿真和分析。结果表明，改进后的协议与原协议相比在复杂度没有明显增加的前提下，降低了平均延时和丢包率，提高了网络性能。     

DDDRC: decentralised data dissemination in VANET using raptor codes

The design of data dissemination protocol has been a great challenge due to the highly dynamic and unreliable wireless channel in vehicular ad hoc networks (VANET). In literature, several interesting solutions are proposed to perform data dissemination for this environment. But these solutions either use architectures requiring centralised coordination or global network knowledge or large intermediate buffers. In this paper, we propose a decentralised technique that overcomes above requirements and provides reliable and scalable communication in both dense and sparse traffic for VANET. Random walks are used in the proposed technique to disseminate data from one vehicle to other vehicles in the network. We use raptor codes to provide low decoding complexity and more scalability for data dissemination. Simulation results demonstrate that the proposed technique has better fault tolerance with lower complexity than general random-walk-based dissemination process and more scalability as compared to the other protocols.     

高斯马尔可夫随机场模型的递归最小二乘参数估计

本文首次提出应用阶递归最小二乘算法来估计高斯马尔可夫随机场模型参数。利用模型参数关于领域的对称性质,我们将一个非因果对称邻域支持的高斯马尔可夫随机场模型转化成一个因果非对称半平面部域支持的模型,从而使递归计算成为可能。利用规范方程中系数矩阵的近似Toeplitz性质,导出了运算量为O(m~3)+O(M~2m)MADP的阶递归最小二乘算法,而直接采用解方程法的计算量为O(m~3)+O(M~2m~2),这里M~2表示一幅图象的尺寸,m代表模型参数的个数。     

Analysis of prediction performance in wavelet minimum complexity echo state network

Echo state network （ESN） has become one of the most popular recurrent neural networks （RNN） for its good prediction performance of non-linear time series and simple training process. But several problems still prevent ESN from becoming a widely used tool. The most prominent problem is its high complexity with lots of random parameters. Aiming at this problem, a minimum complexity ESN model （MCESN） was proposed. In this paper, we proposed a new wavelet minimum complexity ESN model （WMCESN） to improve the prediction accuracy and increase the practical applicability. Our new model inherits the characters of minimum complexity ESN model using the fixed parameters and simple circle topology. We injected wavelet neurons to replace the original neurons in internal reservoir and designed a wavelet parameter matrix to reduce the computing time. By using different datasets, our new model performed better than the minimum complexity ESN model with normal neurons, but only utilized tiny time cost. We also used our own packets of transmission control protocol （TCP） and user datagram protocol （UDP） dataset to prove that our model can deal with the data packet bit prediction problem well.     

随机接入协议:研究综述

随机接入协议(RAP)是数据链路层关键技术之一,总结了主要的随机接入协议的研究现状,并分析了在CDMA网络中协议设计的关键问题。     

AODVCS,a new bio-inspired routing protocol based on cuckoo search algorithm for mobile ad hoc networks

Mobile ad hoc networks (MANETs) are becoming an emerging technology that offer several advantages to users in terms of cost and ease of use. A MANET is a collection of mobile nodes connected by wireless links that form a temporary network topology that operates without a base station and centralized administration. Routing is a method through which information is forwarded from a transmitter to a specific recipient. Routing is a strategy that guarantees, at any time, the connection between any two nodes in a network. In this work, we propose a novel routing protocol inspired by the cuckoo search method. Our routing protocol is implemented using Network simulator 2. We chose Random WayPoint model as our mobility model. To validate our work, we opted for the comparison with the routing protocol ad hoc on-demand distance vector, destination sequence distance vector and the bio-inspired routing protocol AntHocNet in terms of the quality of service parameters: packet delivery ratio and end-to-end delay (E2ED).     

支持用户撤销的属性认证密钥协商协议

用户撤销是基于属性的认证密钥协商(ABAKA, attribute-based authenticated key agreement)协议在实际应用中所必需解决的问题。通过将Waters的基于属性的加密方案和Boneh-Gentry-Waters的广播加密方案相结合,提出了一个支持用户撤销的ABAKA协议。该协议能够实现对用户的即时撤销且不需要密钥权威对所有未被撤销的用户私钥进行定期更新。相比于现有的协议,该协议具有较高的通信效率,并能够在标准模型和修改的ABCK模型下可证安全,具有弱的完美前向安全性,并能够抵抗密钥泄露伪装攻击。     

The IMPORTANT framework for analyzing the Impact of Mobility on Performance Of RouTing protocols for Adhoc NeTworks

A Mobile Ad hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without using any existing infrastructure. Since not many MANETs are currently deployed, research in this area is mostly simulation based. Random Waypoint is the commonly used mobility model in these simulations. Random Waypoint is a simple model that may be applicable to some scenarios. However, we believe that it is not sufficient to capture some important mobility characteristics of scenarios in which MANETs may be deployed. Our framework aims to evaluate the impact of different mobility models on the performance of MANET routing protocols. We propose various protocol independent metrics to capture interesting mobility characteristics, including spatial and temporal dependence and geographic restrictions. In addition, a rich set of parameterized mobility models is introduced including Random Waypoint, Group Mobility, Freeway and Manhattan models. Based on these models several ‘test-suite’ scenarios are chosen carefully to span the metric space. We demonstrate the utility of our test-suite by evaluating various MANET routing protocols, including DSR, AODV and DSDV. Our results show that the protocol performance may vary drastically across mobility models and performance rankings of protocols may vary with the mobility models used. This effect can be explained by the interaction of the mobility characteristics with the connectivity graph properties. Finally, we attempt to decompose the reactive routing protocols into mechanistic “building blocks” to gain a deeper insight into the performance variations across protocols in the face of mobility.     

保护私有信息的点包含协议研究

对现有保护私有信息的点包含协议进行研究,针对算法复杂度高、协议本身的的局限性等问题,在半诚实模型下,提出一种保护隐私的判断点与凸包位置关系协议。首先,利用 与矢量的几何性质,将传统的点线位置判断问题扩展,设计一种茫然安全点线位置关系判断协议;然后,将此协议作为基础协议,结合安全二分检索法提出最终解决方案。利用Goldreich证明法对协议进行安全性证明,同时分析协议的正确性与算法复杂度。分析结果表明,协议在效率上优于现有方案,并具有可扩展性。     

数据采集型传感器网络结构的生成机制研究

对树形网络结构中的3种典型采集树协议,随机采集树生成协议、距离-能量采集树生成协议和负载均匀的采集树生成协议做了详细的介绍,并分析了各个协议的优缺点.结合仿真结果分析了各协议对网络性能的影响.