共查询到20条相似文献,搜索用时 15 毫秒
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《Computer Standards & Interfaces》2006,28(1):75-92
The reliability of the distributed system has always been an important topic of research. Byzantine Agreement (BA) protocol, which allows the fault-free processors to agree on a common value, is one of the most fundamental problems studied in a distributed system. In previous works, the problem was visited in a fully connected network or an unfully connected network with fallible processors. In this paper, the BA problem is reexamined in a group-oriented network, which has the feature of grouping, and the network topology does not have to be fully connected. We also enlarge the fault tolerant capability by allowing dormant faults and malicious faults (also called as the dual failure mode) to exist in a group-oriented network simultaneously. The proposed protocol is more efficient than the traditional BA protocols and can tolerate the maximum number of tolerable faulty processors. 相似文献
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《IEEE transactions on pattern analysis and machine intelligence》1985,(6):539-546
A randomized model of distributed computation was recently presented by Rabin [ 81. This model admits a solution to the Byzantine Agreement Problem for systems of n asynchronous processes where no more than t are faulty. The algorithm described by Rabin produces agreement in an expected number of rounds which is a small constant independent of n and t. Using the same model, we present an algorithm of similar complexity which is able to tolerate a greater portion of malicious processes. The algorithm is also applicable, with minor changes, to systems of synchronous processes. 相似文献
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Ad Hoc网络中一种基于环状分层结构的组密钥协商协议 总被引:1,自引:0,他引:1
移动ad hoc网络是一种新型的移动多跳无线网络.其自身的特征,如网络规模庞大、动态的拓扑结构、有限的计算、通信和存储能力等,使得传统的密钥分配和管理机制无法直接应用于该网络.提出了一种新的适用于移动 ad hoc网络的组密钥协商协议.该协议在环状分层结构上基于多线性映射进行组密钥的协商和分配,使得节点在密钥协商过程中具有低计算开销与低通信开销的优势,较好地解决了在移动ad hoc网络中进行组密钥协商时所遇到的节点能量受限问题,适用于移动ad hoc网络. 相似文献
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It is often important for the correct processes in a distributed system to reach agreement, despite the presence of some faulty processes. Byzantine Agreement (BA) is a paradigm problem that attempts to isolate the key features of reaching agreement. We focus here on the number of messages required to reach BA, with particular emphasis on the number of messages required in thefailure-free runs, since these are the ones that occur most often in practice. The number of messages required is sensitive to the types of failures considered. In earlier work, Amduret al. (1992) established tight upper and lower bounds on the worst- and average-case number of messages required in failure-free runs for crash failures. We provide tight upper and lower bounds for all remaining types of failures that have been considered in the literature on the BA problem: receiving omission, sending omission, and general omission failures, as well as arbitrary failures with or without message authentication. We also establish a tradeoff between number of rounds and number of messages in the failure-free runs required to reach agreement in the case of crash, sending, and general omission failures.The work of V. Hadzilacos was supported, in part, by a grant from the Natural Sciences and Engineering Research Council of Canada. 相似文献
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田跃欣 《数字社区&智能家居》2007,(18)
移动Ad hoc网络是近年来网络研究的热点,WSN(Wireless Sensor Networks,无线传感器网络)是传感器研究领域一个新的研究方向.由于它们之间诸多的相似性使得每当提到WSN的时候往往与Ad hoc网络做比较.本文试图通过对Ad hoc网络和WSN网络特点和路由协议的介绍和分析,使这两个领域区别并联系起来. 相似文献
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基于口令认证的移动Ad Hoc网密钥协商方案 总被引:8,自引:0,他引:8
Ad Hoc网是一种不依赖于任何固定基础设施、没有中心控制节点、计算资源受限的新型无线移动网络.基于ECC(elliptic curves cryptography),提出了一个新的适用于Ad Hoc网的具有口令认证和共享口令进化的多方密钥协商方案.口令的一个功能是作为共享信息认证移动节点的密钥,另一个功能是作为对称密钥加密移动节点间的交互信息.共享口令进化机制保证每次认证节点密钥和协商会话密钥时口令的新鲜性和安全性,从而既减轻了移动节点的计算量和存储负担,又实现了移动节点之间的密钥认证和信息加密.新方案具有抗中间人攻击、抗重放攻击、密钥独立和前向安全等多种安全特性. 相似文献
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We present an efficient, optimally-resilient Asynchronous Byzantine Agreement (ABA) protocol involving $n = 3t+1$ parties over a completely asynchronous network, tolerating a computationally unbounded Byzantine adversary, capable of corrupting at most $t$ out of the $n$ parties. In comparison with the best known optimally-resilient ABA protocols of Canetti and Rabin (STOC 1993) and Abraham et al. (PODC 2008), our protocol is significantly more efficient in terms of the communication complexity. Our ABA protocol is built on a new statistical asynchronous verifiable secret sharing (AVSS) protocol with optimal resilience. Our AVSS protocol significantly improves the communication complexity of the only known statistical and optimally-resilient AVSS protocol of Canetti et al. Our AVSS protocol is further built on an asynchronous primitive called asynchronous weak commitment (AWC), while the AVSS of Canetti et al. is built on the primitive called asynchronous weak secret sharing (AWSS). We observe that AWC has weaker requirements than AWSS and hence it can be designed more efficiently than AWSS. The common coin primitive is one of the most important building blocks for the construction of an ABA protocol. In this paper, we extend the existing common coin protocol to make it compatible with our new AVSS protocol that shares multiple secrets simultaneously. As a byproduct, our new common coin protocol is more communication efficient than all the existing common coin protocols. 相似文献
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This paper considers the Byzantine agreement problem in a completely connected network of anonymous processors. In this network model the processors have no identifiers and can only detect the link through which a message
is delivered. We present a polynomial-time agreement algorithm that requires 3⌊(n−t)t/(n−2t)⌋+4 rounds, where n>3t is the number of processors and t is the maximal number of faulty processors that the algorithm can tolerate. We also present an early-stopping variant of
the algorithm. 相似文献
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We consider the problem of computing Byzantine Agreement in a synchronous network with n processors, each with a private random string, where each pair of processors is connected by a private communication line.
The adversary is malicious and non-adaptive, i.e., it must choose the processors to corrupt at the start of the algorithm.
Byzantine Agreement is known to be computable in this model in an expected constant number of rounds. We consider a scalable
model where in each round each uncorrupt processor can send to any set of log n other processors and listen to any set of log n processors. We define the loss of an execution to be the number of uncorrupt processors whose output does not agree with the output of the majority of uncorrupt
processors. We show that if there are t corrupt processors, then any randomised protocol which has probability at least 1/2 + 1/ logn of loss less than requires at least f rounds. This also shows that lossless protocols require both rounds, and for at least one uncorrupt processor to send messages during the protocol. 相似文献
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《Computer Standards & Interfaces》2006,28(4):475-492
Networks are trending towards wireless systems that provide support for mobile computing. The Byzantine Agreement (BA) protocols used in static networks do not perform well in a dynamically changing mobile environment. Mobile commerce and related applications are necessary for wireless networks. There are numerous properties in a wireless network that play important roles. For example, the processors in a wireless network have highly mobile capabilities. Processors can immigrate into or move away from the network at any time. Although mobile technology has brought greater convenience, it is comparatively more dangerous. Wireless systems are susceptible to security flaws such as attacks by hackers. The number of allowable faulty components within the system is also decreased. To increase the number of allowable faulty components and ensure network security, a simple, secure and efficient protocol, BAM, is proposed to handle the BA problem. The fault symptoms include malicious and dormant faults. Furthermore, the proposed protocol uses the minimum number of message exchange rounds to make all healthy processors agree on a common value and can tolerate the maximum number of allowable faulty components. The proposed method will also ensure message security and increase the system's fault tolerant capability. 相似文献
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Wang S.C. Chin Y.H. Yan K.Q. 《Parallel and Distributed Systems, IEEE Transactions on》1995,6(4):420-427
Traditionally, the Byzantine Agreement (BA) problem is studied either in a fully connected network or in a broadcast network. A generalized network model for BA is proposed in this paper. A fully-connected network or a broadcast network is a special case of the new network architecture. Under the new generalized network model, the BA problem is reexamined with the assumption of malicious faults on both processors and transmission medium (TM), as opposed to previous studies which consider malicious faults on processors only. The proposed algorithm uses the minimum number of message exchanges, and can tolerate the maximum number of allowable faulty components to make each healthy processor reach a common agreement for the cases of processor failures, TM failures, or processor/TM failures. The results can also be used to solve the interactive consistency problem and the consensus problem 相似文献
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《International journal of human-computer interaction》2013,29(3):313-315
This article considers the nature of e-mail from the recipient's perspective-what the seemingly free and easy communication really costs the recipient. Information gathered by electronic monitoring software is shown to be at odds with the results of an online survey of e-mail users' perceptions of their e-mail experience-users drastically underestimate the disruptive effects of e-mail. The conclusion is that the constant monitoring of e-mail actually reduces productivity and that there is a need for increased power, control, and awareness on the part of the e-mail recipient to ensure that e-mail remains a tool rather than a tyrant. It is necesssary to alert the user of the true cost of e-mail alerts. 相似文献