Security Analysis of Broadcaster Group Key Exchange Protocols

Group key exchange protocols are basic protocols to provide privacy and integrity in secure group communication. This paper discusses the security of one type of group key exchange protocols and defines the kind of protocols as broadcaster group protocols. It points out two attacks on this kind of protocols. The first attack can be avoided by using fresh values in each action during one session of the group protocol. The second attack should be related with concrete application. It also proposes a dynamic key agreement protocol as an example of solutions at the last part of the paper.

Universally Composable Symbolic Analysis of Group Key Exchange Protocol

Canetti and Herzog have already proposed universally composable symbolic analysis(UCSA) to analyze mutual authentication and key exchange protocols. However,they do not analyze group key exchange protocol. Therefore,this paper explores an approach to analyze group key exchange protocols,which realize automation and guarantee the soundness of cryptography. Considered that there exist many kinds of group key exchange protocols and the participants’ number of each protocol is arbitrary. So this paper takes the case of Burmester-Desmedt(BD) protocol with three participants against passive adversary(3-BD-Passive) . In a nutshell,our works lay the root for analyzing group key exchange protocols automatically without sacrificing soundness of cryptography.

A Novel Approach towards Cost Effective Region-Based Group Key Agreement Protocol for Ad Hoc Networks Using Elliptic Curve Cryptography

This paper addresses an interesting security problem in wireless ad hoc networks: the dynamic group key agreement key establishment. For secure group communication in an ad hoc network, a group key shared by all group members is required. This group key should be updated when there are membership changes (when the new member joins or current member leaves) in the group. In this paper, we propose a novel, secure, scalable and efficient region-based group key agreement protocol for ad hoc networks. This is implemented by a two-level structure and a new scheme of group key update. The idea is to divide the group into subgroups, each maintaining its subgroup keys using group elliptic curve diffie-hellman (GECDH) Protocol and links with other subgroups in a tree structure using tree-based group elliptic curve diffie-hellman (TGECDH) protocol. By introducing region-based approach, messages and key updates will be limited within subgroup and outer group;hence computation load is distributed to many hosts. Both theoretical analysis and experimental results show that this Region-based key agreement protocol performs well for the key establishment problem in ad hoc network in terms of memory cost, computation cost and communication cost.

A novel approach to authenticated group key transfer protocol based on AG codes

Group key management technique is a fundamental building block for secure and reliable group communication systems.In order to successfully achieve this goal, group session key needs to be generated and distributed to all group members in a secure and authenticated manner.The most commonly used method is based on Lagrange interpolating polynomial over the prime field F p={0,1,2,…, p-1}. A novel approach to group key transfer protocol based on a category of algebraic-geometry code is presented over the infinite field GF(2 m). The attractive advantages are obvious. Especially, the non-repeatability, confidentiality, and authentication of group key transfer protocols are obtained easily. Besides, a more generalized and simple mathematical construction model is proposed which also can be applied perfectly to related fields of information security.

Formal Verification of Secrecy in Group Key Protocols Using Event-B

Group key security protocols play an important role in today’s communication systems. Their verification, however, remains a great challenge because of the dynamic characteristics of group key construction and distribution protocols. Security properties that are well defined in normal two-party protocols have different meanings and different interpretations in group key distribution protocols, specifically, secrecy properties, such as group secrecy, forward secrecy, backward secrecy, and key independence. In this paper, we present a method to verify forward secrecy properties for group-oriented protocols. The method is based on a correct semantical link between group key protocols and event-B models and also uses the refinement process in the B method to model and verify group and forward secrecy. We use an event-B first-order theorem proving system to provide invariant checking for these secrecy properties. We illustrate our approach on the Tree based Group Diffie-Hellman protocol as case study.

Protocol for a Diagnostic Accuracy Study of Polymerase Chain Reaction for Detecting Group B <i>Streptococcus</i>Colonisation in Early Labour or with Spontaneous Ruptured Membranes

Background: Group B Streptococcus [GBS] is a bacterium which transiently colonises the genital tract and can be transmitted from mother to baby at birth. Babies colonised with GBS can develop early-onset group B streptococcus disease [EOGBSD] which can lead to extended hospital stay, disability and death. One of the primary methods for determining which women are most likely to be GBS positive at the time of birth is antenatal universal culture-based screening. Recently Polymerase Chain Reaction [PCR] screening has emerged as a point-of-care method for screening women during the intrapartum period. This study will compare the diagnostic accuracy of this new technology and antenatal culture-based screening at 35 to 37 weeks gestational age, with the reference standard of formal culture-based testing in labour. Methods: This prospective observational study will take place in an Australian hospital. Consecutive women with one or more live fetuses, intending to have a vaginal birth will be asked to participate. Planned screening for GBS colonisation using microbiological culture on a self-collected specimen will occur at 35 to 37 completed weeks gestational age as per our usual hospital policy. A PCR GBS test by Xpert GBS (Cepheid) will be performed on admission to labour ward or at the time of rupture of membranes. The reference standard will be a formal GBS culture on a combined lower vaginal and perianal swab. The sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios will be estimated for both antenatal screening and the intrapartum Xpert GBS (Cepheid) point-of-care test and compared to the reference standard. Results: It is expected that the study will be completed by mid to late 2020. Conclusion: This study has the potential to improve the accuracy of GBS screening of pregnant women and therefore health outcomes for mothers and babies. There is also the potential for a cost savings to the health system.

Exploring Application Layer Protocol Relationships in SoftSwitch

Relationships between application layer protocols in softswitch are explored in this paper.Two notions, i.e.protocol relationship and protocol grouping, are proposed, which are not clearly defined and even not paid much attention to before.On the basis of a well known protocol relationship named protocol conversion, three novel protocol relationships including protocol collaboration relationship, protocol cooperation relationship and protocol independent relationship are presented, so that protocol relationships are classified into four types.According to the functionality and purpose of each protocol, main protocols related to softswitch are divided into five groups.As to protocol conversion in softswitch, information flow trail(IFT) is utilized to facilitate problem solving.A decision rule for protocol conversion mode is proposed to guide how to choose between direct conversion and indirect conversion.A property of protocol relationships in softswitch is induced from all kinds of service scenarios of softswitch.This property summarizes protocol relationships within each protocol group or between two specific protocol groups.A merit of protocol grouping together with classification of protocol relationship is also presented.The effort of this paper pushes the protocol engineering to go ahead.

Formal Verification in 3oux Tripartite Diffie-Hellman Protocol

Security analysis of cryptographic protocols has been widely studied for many years.As far as we know,we have not found any methods to effectively analyze group key exchange protocols for the three parties yet,which did not sacrifice the soundness of cryptography.Recently,Canetti and Herzog have proposed Universally Composable Symbolic Analysis(UCSA) of two-party mutual authentication and key exchange protocol which is based on the symmetric encryption schemes.This scheme can analyze the protocols automatically and guarantee the soundness of cryptography.Therefore,we discuss group key exchange protocol which is based on Joux Tripartite Diffie-Hellman(JTDH) using UCSA.Our contribution is analyzing group key exchange protocol effectively without damaging the soundness of cryptography.

CCCG-ALL-2015方案治疗儿童急性淋巴细胞白血病复发的危险因素分析

目的分析儿童急性淋巴细胞白血病(acute lymphoblastic leukemia,ALL)经中国儿童肿瘤协作组急性淋巴细胞白血病2015方案(Chinese Children's Cancer Group ALL-2015 protocol,CCCG-ALL-2015)治疗后的累积复发率(cumulative incidence of relapse,CIR),并探讨影响复发的危险因素。方法回顾性分析2015年1月—2019年12月接受CCCG-ALL-2015方案治疗的852例患儿的临床资料,计算CIR并分析影响儿童急性B淋巴细胞白血病(B-ALL)复发的危险因素。结果852例ALL患儿中,146例(17.1%)发生复发,8年CIR为(19.8±1.6)%。B-ALL与急性T淋巴细胞白血病患儿的8年CIR比较差异无统计学意义(P>0.05)。146例复发患儿中,复发时间主要集中于极早期(62例,42.5%)和早期(46例,31.5%),极早期单纯骨髓复发42例(28.8%),早期单纯骨髓复发27例(18.5%)。Cox比例风险回归模型分析显示,融合基因MLLr阳性(HR=4.177,95%CI:2.086~8.364,P<0.001)和第46天微小残留病≥0.01%(HR=2.013,95%CI:1.163~3.483,P=0.012)是B-ALL患儿经CCCG-ALL-2015方案治疗后复发的危险因素。结论儿童ALL经CCCG-ALL-2015方案治疗后仍有较高的复发率,以极早期和早期单纯骨髓复发常见;第46天微小残留病≥0.01%、融合基因MLLr阳性与B-ALL复发密切相关。

Reformative multicast routing protocol based on Ad Hoc

Mobile Ad Hoc networks has been widely applied to military field, emergency management, public service and so on. Because it is uncertain on network and communication, a great deal of energy will be consumed with nodes increasing and creating routing each other. The reformative on-demand multicast routing protocol was putted forward by researching the energy consuming of multicast routing protocol in Ad Hoc. It will decrease consumption in a big multicast flooding through studying the relaying group net structure based on map or wormhole. The energy consumption is reduced 30% by creating the two kinds of routing principles: minimization of energy consumption and minimization of maximum nodes energy consumption. The simulation result indicates that the reformative RODMRP is effective to reduce the energy consuming while routing protocol built.

New Public Key Cryptosystems from Combinatorial Group Theory

External direct product of some low layer groups such as braid groups and general Artin groups, with a kind of special group action on it, provides a secure cryptographic computation platform, which can keep secure in the quantum computing epoch. Three hard problems on this new platform, Subgroup Root Problem, Multi-variant Subgroup Root Problem and Subgroup Action Problem are presented and well analyzed, which all have no relations with conjugacy. New secure public key encryption system and key agreement protocol are designed based on these hard problems. The new cryptosystems can be implemented in a general group environment other than in braid or Artin groups.

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。

Cryptographic Protocols Based on Nielsen Transformations

We introduce in this paper cryptographic protocols which use combinatorial group theory. Based on a combinatorial distribution of shares we present secret sharing schemes and cryptosystems using Nielsen transformations. Nielsen transformations are a linear technique to study free groups and general infinite groups. In addition the group of all automorphisms of a free group F, denoted by AUT (F), is generated by a regular Nielsen transformation between two basis of F, and each regular Nielsen transformation between two basis of F defines an automorphism of F.

A Fair Electronic Cash System with Identity-Based Group Signature Scheme

A fair electronic cash system is a system that allows customers to make payments anonymously. Furthermore the trusted third party can revoke the anonymity when the customers did illegal transactions. In this paper, a new fair electronic cash system based on group signature scheme by using elliptic curve cryptography is proposed, which satisfies properties of secure group signature scheme (correctness, unforgeability, etc). Moreover, our electronic cash contains group members (users, merchants and banks) and trusted third party which is acted by central bank as group manager.

Advanced Transition/Cluster Key Management Scheme for End-System Multicast Protocol

The recent growth of the World Wide Web has sparked new research into using the Internet for novel types of group communication, like multiparty videoconferencing and real-time streaming. Multicast has the potential to be very useful, but it suffers from many problems like security. To achieve secure multicast communications with the dynamic aspect of group applications due to free membership joins and leaves in addition to member's mobility, key management is one of the most critical problems. So far, a lot of multicast key management schemes have been proposed and most of them are centralized, which have the problem of 'one point failure' and that the group controller is the bottleneck of the group. In order to solve these two problems, we propose a Key Management Scheme, using cluster-based End-System Multicast (ESM). The group management is between both 1) the main controller (MRP, Main Rendezvous Point) and the second controllers (CRP, Cluster RP), and 2) the second controllers (CRPs) and its members. So, ESM simplifies the implementation of group communication and is efficient ways to deliver a secure message to a group of recipients in a network as a practical alternative to overcome the difficulty of large scale deployment of traditional IP multicast. In this paper, we analyze different key management schemes and propose a new scheme, namely Advanced Transition/Cluster Key management Scheme (ATCKS) and find it has appropriate performance in security.

一种改进的群组机器人网络路由算法

针对群组机器人系统在应急场景下移动频繁、能量有限的特点,提出了一种基于能量与速度的分簇自组织按需距离矢量协议(Clustered Ad hoc On-Demand Distance Vector Protocol Based on Energy and Speed,ESC-AODV),以延长群组机器人网络运行时间,提高通信可靠性。用路由性能代替跳数作为路由判据,目的节点在重复接收到路由请求(Route Request,RREQ)数据包时,若路由性能更小,则回复路由应答(Routing Reply,RREP)数据包,以此选择更好的路由,引入分簇结构,通过簇头和网关组成的骨干网络减少广播洪泛次数。实验结果证明,节点数量多时,改进的ESC-AODV协议在延长网络生存时间的同时,平均端到端时延、数据包投递率、吞吐量和路由开销均优于AODV以及基于能量、负载和速度的AODV路由协议(AODV Routing Protocol Based on Energy,Load and Speed,ELS-AODV)。ESC-AODV协议能够节约网络能量,提高可靠性,获得更优的网络性能。

波塞冬1组患者重复周期应用早卵泡期长效长方案和拮抗剂方案的疗效比较及自身对照研究

目的探讨早卵泡期长效长方案和拮抗剂方案在波塞冬1组患者重复周期中的应用疗效及优化策略。方法选择2018年6月至2022年6月于安徽省妇幼保健院生殖中心行体外受精(IVF)/卵胞浆内单精子注射(ICSI)治疗、采用常规控制性促排卵(COH)方案发生非预期卵巢低反应(uPOR)、且助孕失败后再次助孕的波塞冬1组患者286例为研究对象,根据重复周期COH方案不同分为早卵泡期长效长方案组(简称早长方案组,n=119例)和拮抗剂方案组(n=167例),比较两组实验室指标及临床妊娠结局;并将其中前后两个周期均采用相同COH方案的124例患者分为双早长方案组(n=70例)和双拮抗剂方案组(n=54例),采用自身对照研究分析两组临床资料。结果(1)再次COH周期早长方案组与拮抗剂方案组患者间基础资料比较无统计学差异(P>0.05)。早长方案组促性腺激素(Gn)总量、Gn天数、HCG日E_(2)水平、获卵数、可用胚胎数及优质胚胎数均显著高于拮抗剂方案组(P<0.05),HCG日LH水平显著低于拮抗剂方案组(P<0.05),其鲜胚种植率、鲜胚临床妊娠率及累积妊娠率较拮抗剂方案组有升高趋势,但无统计学差异(P>0.05);两组患者间周期取消率、中重度卵巢过度刺激综合征(OHSS)发生率、HCG日孕酮(P)水平、HCG日内膜厚度、再次uPOR发生率及早期流产率等比较均无统计学差异(P>0.05)。(2)双早长方案组的自身对照比较结果显示,再次早长方案组Gn启动剂量、LH添加量、HCG日E_(2)水平、获卵数、可用胚胎数、优质胚胎数、正常受精率、优质胚胎率、鲜胚种植率和临床妊娠率均显著高于首次早长方案组(P<0.05),早期流产率显著低于首次早长方案组(P<0.05)。(3)双拮抗剂方案组的自身对照比较结果显示,再次拮抗剂方案组Gn启动剂量、LH添加量、获卵数、可用胚胎数、优质胚胎数、鲜胚种植率及临床妊娠率等均显著高于首次拮抗剂方案组(P<0.05)。结论对于波塞冬1组患者来说,早卵泡期长效长方案和拮抗剂方案均可作为重复周期的促排卵方案;从获卵数及鲜胚临床妊娠结局考虑,早卵泡期长效长方案优于拮抗剂方案;从经济成本考虑,拮抗剂方案优于早卵泡期长效长方案。重复周期可根据两个方案的劣势采取优化措施来改善患者对于促排卵方案的反应性及卵母细胞质量和数量等问题,从而改善IVF/ICSI预后。

基于以太网的列车灵活编组技术实现及研究

灵活编组功能是配合铁道车辆灵活运用的网络技术,不仅响应复杂变化的运维条件,而且提高了轨道交通装备网络配置的效率。基于以太网的灵活编组技术通过IEC61375-2-5协议中的网络初运行、列车拓扑发现协议实现,对于解决列车网络系统的应用问题具有较高的参考价值。

基于CSIDH的认证密钥交换协议

针对Galbraith等提出的基于超奇异同源的认证密钥交换协议存在的安全问题,通过使用NAXOS技巧,并将通信双方静态密钥的Diffie-Hellman值添加到会话密钥的计算中,提出一个新的基于CSIDH的两轮认证密钥交换协议,并给出安全性证明。该协议是目前第一个基于CSICDH问题假设,且在eCK模型下可证明安全的认证密钥交换协议。经对比,该协议具有更强的安全属性,具体表现在可抵抗最大暴露攻击和自适应性攻击等方面。

Anycast——IP的又一通信模式

Anycast是一种新型的网络服务 ,是IPv6的一个新特 性 与unicast和multicast一样 ,它是IP的一种通信模式 Anycast给用户的期望是通过一个anycast地址就能访问到该地址所表示的一组服务器中对用户来说距离最近的一 个 Anycast的应用空间非常广 阔 但是 ,它的实现还面临着许多问题 现在 ,anycast研究者的注意力主要集中在路由协议、无状态服务问题、组管理协议、局域网通信、地址结构、安全问题、QoS保证以及可扩展性等方面 有些方面已经取得了一些进展 但是 ,仍然有许多研究工作有待进一步开展 关于anycast的一些协议和标准正在讨论之中 ,但仍然没有达成共 识 作为下一代Internet新兴的服务方式 ,anycast为我们展开了广阔的探索空