面向物联网的高效集群证明机制

随着物联网的迅速发展,巨量的嵌入式设备广泛应用于现代生活,安全和隐私成为了物联网发展的重要挑战.物联网设备互联构成集群网络,设备集群证明是验证集群环境内所有设备的可信状态的一种安全技术,也是物联网安全研究需要解决的一个重要问题.传统证明技术主要针对单一证明者的场景,无法满足大规模集群的全局证明需求;而简单扩展的集群证明机制通常难以抵抗合谋攻击,且效率低下.为了解决这些问题,本文提出了一种基于设备分组的高效集群证明方案.该方案将同构设备分组,并于每组设立一个管理节点负责该组的组内节点验证.当进行远程证明时,由于每个管理节点已经预先获悉该组节点可信性状态,所以只需要对全局集群环境内所有管理节点进行验证,从而提高了效率.该方案不仅高效,还具有较高的安全性,能够抵抗合谋攻击等.我们实现的原型系统实验测试结果表明,当同构设备越多,管理节点越少的时候,本文方案的证明效率更高.

面向物联网设备的安全集群证明及修复协议

由于物联网设备本身缺少安全机制,物联网环境面临着严峻的安全挑战.而远程证明能够认证设备真实性和完整性,可以通过远程方式建立对物联网设备的信任.集群证明是远程证明技术的扩展,可以适用于大量设备构成的集群.相较于传统的远程证明,集群证明解放了验证设备,提高了验证的效率.目前,集群证明方法主要是针对静态网络,而且对于受损设备也缺乏高效的修复机制.针对这些问题,本文提出了一种基于信誉机制和Merkle树的安全集群证明及修复方法.首先,本文方法使用信誉机制实现了多对一的证明协议,能有效解决单点故障,从设备触发验证,并且能够适用于半动态网络.其次,本文引入Merkle树进行度量,能够快速地识别被感染的代码块,并进行高效地恢复;最后,本文对提出的集群证明方法进行了安全性分析和性能评估,结果表明,本文集群证明在提高了安全性的同时导致的性能开销是可以接受的.

一种无序匿名的RFID群证明方案

现有无线射频识别(RFID)群证明方案中的群证明生成效率较低。针对该问题,基于椭圆曲线离散对数困难性问题,采用多重签名的思想,并行且匿名地生成群证明。理论分析结果表明,该方案满足安全性和隐私性要求,与同类方案相比,只需一次点乘即可生成群证明,效率更高。

一种采用双层校验的RFID离线匿名群证明协议

随着越来越多的物品被贴上RFID标签,用于证明若干具有一定关系的物品作为一个群组在同一时间、同一地点出现的群证明技术的应用日趋广泛.在RFID群证明技术中,如何在确保标签信息安全与隐私的同时,生成可靠的群证明,并提升协议的执行效率是当前的研究热点.为确保标签信息的安全与隐私,离线群证明协议往往仅由Verifier完成验证,Reader仅负责群证明信息的收集,降低了协议对于非法群证明的响应速度,为提高系统的群证明效率,抵御拒绝服务(deny of proof,DoP)攻击,提出了一种采用双层校验的RFID离线匿名群证明协议AGPDL,使用椭圆曲线加密,通过二次校验的方法,授权Reader在标签匿名的情况下预先进行群证明的有效性验证,然后再由Verifier完成最终的群证明校验,并确认标签身份.通过安全性分析与性能分析可知:AGPDL能够较好地保护标签信息的安全与隐私,抵御冒充攻击与重放攻击,并且防止Reader提交无效群证明带来的系统开销,具有较好的可扩展性.

基于字合成运算的标签组群组共存证明协议

针对现有的大多数证明协议无法同时证明多标签同时存在缺陷,提出一种具有可扩展性的电子标签组证明协议。协议采用按位运算设计实现的字合成运算对信息加密,字合成运算可使得协议达到超轻量级计算;同时字合成运算实现中巧妙运用参数自身具备的汉明重量,可减少参量引入;协议基于先验证再响应机制,可抵抗假冒攻击等。对协议进行不同角度分析,表明协议能够提供较高的安全性能,同时能够适用于现有低成本被动式电子标签系统中。

可抗穷举攻击的射频识别群组证明协议

针对孙达志等提出的群组证明协议进行重点分析,指出协议存在无法抗穷举攻击的安全缺陷,并在此基础上给出一个改进的协议。协议采用遍历取反运算对信息加密,遍历取反运算将根据加密参量自身汉明重量大小不同而进行对不同参量的取反操作,增加破解难度;协议将信息加密之后再发送,同时信息加密时确保多个参量攻击者无法知晓,以此来抵抗穷举攻击。从安全性角度分析协议,表明协议具有较好的安全性能;从仿真实验角度分析协议,表明协议具有计算量低的优势。

一种基于远程证明的智能制造设备群的主动防御方案

随着人工智能技术的发展,智能制造已成为目前企业生产的必然选择.然而与此同时,智能制造设备群面临的安全风险也不断上升,一个被入侵的智能制造设备不仅会造成机密泄露、生产链错误等问题,还会成为攻击者的跳板进而影响整个设备群的安全.设计了一种基于远程证明的智能制造系统设备群的主动防御方案SecRA,以验证设备群的安全状态.SecRA对每个智能制造设备都生成独立的证明挑战,实现了网关和设备间点到点通信,保证了该主动防御方法的安全性.SecRA通过对智能制造系统中网关设备的功能扩展,完成验证者和设备之间的异步通信,以匹配现有智能制造系统网络结构.此外,SecRA基于挑战-质询的证明协议,将通信和计算开销都转移到资源丰富的网关设备,极大节省了设备端的开销.最后,仿真实验证明了SecRA主动防御方法的高效性和可行性.

一种轻量级隐私保护的RFID群组证明协议

设计高效安全的群组证明协议有利于RFID(Radio Frequency Identification)系统的广泛应用.本文提出了一种轻量级隐私保护的RFID群组证明协议LPGP(Lightweight Privacy-Preserving Grouping Proof),LPGP协议只使用计算复杂度比较小的伪随机发生器和散列运算来提高协议的运行效率,并且LPGP协议具有认证性、隐私性和可证明安全性,满足了RFID系统群组证明协议的安全性要求.与现有的群组证明协议相比,LPGP协议的标签只需较小的计算复杂度和存储空间,具有较高的效率.

改进的RFID群组证明协议

针对射频识别(RFID)群组证明协议中的安全和隐私问题,重点分析Cho等提出的一种RFID群组证明协议中存在的交错攻击问题,在此基础上,提出一种改进的RFID群组证明协议。利用消息认证码和伪随机数生成器等加密技术,以及计算结构上的不对称性,保障协议的安全和隐私。安全分析结果表明,该协议与其它相关协议相比具有更强的安全性和更好的隐私保护。将该协议扩展为相对应的针对多个RFID标签的群组证明协议。

云存储中支持数据去重的群组数据持有性证明

数据持有性证明(provable data possession,简称PDP)和数据可恢复性证明(proofs of retrievability,简称POR)是客户端用来验证存储在云端服务器上数据完整性的主要技术.近几年,它在学术界和工业界的应用广泛,很多PDP和POR方案相继出现.但是由于不同群组的特殊性和独特要求,使得群组PDP/POR方案多样化,并且群组应用中的许多重要功能(例如数据去重)没有被实现.如何构造高效及满足群组特定功能和安全需求的PDP/POR方案,已经引起了人们的广泛关注.给出了一种支持数据去重的群组PDP方案(GPDP),基于矩阵计算和伪随机函数,GPDP可以在支持数据去重的基础上,高效地完成数据持有性证明,并且可以在群组中抵抗恶意方选择成员攻击.在标准模型下证明了GPDP的安全性,并且在百度云平台上实现了GPDP的原型系统.为了评估方案的性能,使用了10GB的数据量进行实验和分析,结果表明:GPDP方案在达到群组中数据去重的目标的基础上,可以高效地保证抵抗选择攻击和数据持有性,即:预处理效率高于私有验证方案,而验证效率高于公开验证方案(与私有验证效率几乎相同).另外,与其他群组PDP/POR方案相比,GPDP方案将额外存储代价和通信代价都降到了最低.

基于群组证明的智能警务设备安全认证协议

随着物联网通信和计算技术的发展,智能警务设备成为未来公安单警装备配备的发展趋势,为公安机关民警执行任务提供高效可靠的移动警务终端服务支持。面向警务云环境下的智能警务设备,设计一种基于群组证明的安全认证协议。该协议考虑智能警务设备及终端交互的空中接口可能存在的安全威胁和系统脆弱点,引入轻量级的密码学算子实现智能警务设备的安全身份认证。该协议采用伪随机序列发生器、Hash函数和密值随机化等安全机制实现了数据机密性和数据完整性、本地和远程身份认证,以及会话周期的不可链接性,适用于轻量级的智能警务设备应用场景。

Membrane-inspired quantum bee colony optimization and its applications for decision engine

In order to effectively solve combinatorial optimization problems,a membrane-inspired quantum bee colony optimization(MQBCO)is proposed for scientific computing and engineering applications.The proposed MQBCO algorithm applies the membrane computing theory to quantum bee colony optimization(QBCO),which is an effective discrete optimization algorithm.The global convergence performance of MQBCO is proved by Markov theory,and the validity of MQBCO is verified by testing the classical benchmark functions.Then the proposed MQBCO algorithm is used to solve decision engine problems of cognitive radio system.By hybridizing the QBCO and membrane computing theory,the quantum state and observation state of the quantum bees can be well evolved within the membrane structure.Simulation results for cognitive radio system show that the proposed decision engine method is superior to the traditional intelligent decision engine algorithms in terms of convergence,precision and stability.Simulation experiments under different communication scenarios illustrate that the balance between three objective functions and the adapted parameter configuration is consistent with the weights of three normalized objective functions.

Stable Rank One and Real Rank Zero for Crossed Products by Finite Group Actions with the Tracial Rokhlin Property

The authors prove that the crossed product of an infinite dimensional simple separable unital C*-algebra with stable rank one by an action of a finite group with the tracial Rokhlin property has again stable rank one. It is also proved that the crossed product of an infinite dimensional simple separable unital C*-algebra with real rank zero by an action of a finite group with the tracial Rokhlin property has again real rank zero.

FPn-Injective, FPn-Flat Covers and Preenvelopes, and Gorenstein AC-Flat Covers

We prove that, for any n 〉 2, the classes of FPn-injective modules and of FPn-flat modules are both covering and preenveloping over any ring R. This includes the case of FP∞-injective and FP∞-flat modules （i.e., absolutely clean and, respectively, level modules）. Then we consider a generalization of the class of （strongly） Gorenstein flat modules, i.e., the （strongly） Gorenstein AC-flat modules （cycles of exact complexes of flat modules that remain exact when tensored with any absolutely clean module）. We prove that some of the properties of Gorenstein fiat modules extend to the class of Gorenstein AC-flat modules; for example, we show that this class is precovering over any ring R. We also show that （as in the case of Gorenstein flat modules） every Gorenstein AC-flat module is a direct summand of a strongly Gorenstein AC-flat module. When R is such that the class of Gorenstein AC-flat modules is closed under extensions, the converse is also true. Moreover, we prove that if the class of Gorenstein AC-flat modules is closed under extensions, then it is covering.

Onset of the Kwangsian Orogeny as evidenced by biofacies and lithofacies

The onset timing of the Kwangsian Orogeny might differ among localities across South China.Refined stratigraphic works at different localities are necessary to reveal the details of this likely distinction.Recently,we recollected some graptolite specimens from the Ordovician Shixing and Longtouzhai formations(corresponding to the Longxi Formation of southern Jiangxi Province) at many localities in Guangdong Province.The palaeontological and biostratigraphical studies of these graptolite faunas indicate that the facies change from graptolitic shale to nearshore shallow-water,coarse clastics in Guangdong is slightly earlier than that in southern Jiangxi.This timing difference may imply a northward progression of the Kwangsian Orogeny.Based on the biostratigraphy and palaeontology of the Ordovician in the Zhujiang Basin(western part) and Chiangnan Slope Belt(including western Fujian,eastern Guangdong,northern Guangxi,northern Hunan,northeastern Jiangxi,southern Anhui,and western Zhejiang),the Sandbian to late Katian distribution and replacement of biofacies and lithofacies in the two regions are proposed and discussed,which display distinct features at different stages of the Kwangsian Orogeny.

Inhibition of BET selectively eliminates undifferentiated pluripotent stem cells

Embryonic stem cells （ESCs） maintain their cellular identity through the systematic regulation of master transcription factors and chromatin remodeling complexes. Recent work has shown that the unusually large-scale enhancers-namely super-enhancers （SEs）, on which BRD4, a member of the bromodomain and extraterminal domain （BET） family is highly enriched-could regulate pluripotency-related transcrip- tion factors. Moreover, inhibition of BRD4 binding on SEs has been shown to induce the differentiation of ESCs. However, the underlying mechanism of BRD4 inhibition-mediated stern cell differentiation remains elusive. Here we show that both mouse and human ESCs lose their capacity for self-renewal upon treat- ment with JQ1, a selective inhibitor of BET family including BRD4, with rapid suppression of pluripotency-associated genes. Notably, a high concentration of JQI could selectively eliminate ESCs via apoptosis, without affecting the functionality of differentiated somatic cells from ESCs, suggesting that inhibition of BET may have a beneficial effect on the development of pluripotent stem cell-based cell therapy.

ON ABELIAN AUTOMORPHISM GROUPS OF SURFACES OF GENERAL TYPE

It is proved that for a complex minimal smooth projective surface S of general type, its abelian automorphism group is of order≤36k2s+24, provided x(os)≥8, where Ks is the canonical divisor of S, and X(Os) the Euler characteristic of the structure sheaf of S.

Coarse Embedding into Uniformly Convex Banach Spaces

In this paper, the author studies the coarse embedding into uniformly convex Banach spaces. The author proves that the property of coarse embedding into Banach spaces can be preserved under taking the union of the metric spaces under certain condi- tions. As an application, for a group G strongly relatively hyperbolic to a subgroup H, the author proves that B（n） = {g ∈ G／ │g│suЭe≤ n} admits a coarse embedding into a uniformly convex Banach space if H does.