33,739 research outputs found

    Forward Security in Threshold Signature Schemes

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    We consider the usage of forward security with threshold signature schemes. This means that even if more than the threshold number of players are compromised, some security remains: it is not possible to forge signatures relating to the past. In this paper, we describe the first forward-secure threshold signature schemes whose parameters (other than signing or verifying time) do not vary in length with the number of time periods in the scheme. Both are threshold versions of the Bellare-Miner forward-secure signature scheme, which is Fiat-Shamir-based. One scheme uses multiplicative secret sharing, and tolerates mobile eavesdropping adversaries. The second scheme is based on polynomial secret sharing, and we prove it forward-secure based on the security of the Bellare-Miner scheme. We then sketch modifications which would allow this scheme to tolerate malicious adversaries. Finally, we give several general constructions which add forward security to any existing threshold scheme

    Security and Privacy Issues in Wireless Mesh Networks: A Survey

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    This book chapter identifies various security threats in wireless mesh network (WMN). Keeping in mind the critical requirement of security and user privacy in WMNs, this chapter provides a comprehensive overview of various possible attacks on different layers of the communication protocol stack for WMNs and their corresponding defense mechanisms. First, it identifies the security vulnerabilities in the physical, link, network, transport, application layers. Furthermore, various possible attacks on the key management protocols, user authentication and access control protocols, and user privacy preservation protocols are presented. After enumerating various possible attacks, the chapter provides a detailed discussion on various existing security mechanisms and protocols to defend against and wherever possible prevent the possible attacks. Comparative analyses are also presented on the security schemes with regards to the cryptographic schemes used, key management strategies deployed, use of any trusted third party, computation and communication overhead involved etc. The chapter then presents a brief discussion on various trust management approaches for WMNs since trust and reputation-based schemes are increasingly becoming popular for enforcing security in wireless networks. A number of open problems in security and privacy issues for WMNs are subsequently discussed before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the author's previous submission in arXiv submission: arXiv:1102.1226. There are some text overlaps with the previous submissio

    On Secure Workflow Decentralisation on the Internet

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    Decentralised workflow management systems are a new research area, where most work to-date has focused on the system's overall architecture. As little attention has been given to the security aspects in such systems, we follow a security driven approach, and consider, from the perspective of available security building blocks, how security can be implemented and what new opportunities are presented when empowering the decentralised environment with modern distributed security protocols. Our research is motivated by a more general question of how to combine the positive enablers that email exchange enjoys, with the general benefits of workflow systems, and more specifically with the benefits that can be introduced in a decentralised environment. This aims to equip email users with a set of tools to manage the semantics of a message exchange, contents, participants and their roles in the exchange in an environment that provides inherent assurances of security and privacy. This work is based on a survey of contemporary distributed security protocols, and considers how these protocols could be used in implementing a distributed workflow management system with decentralised control . We review a set of these protocols, focusing on the required message sequences in reviewing the protocols, and discuss how these security protocols provide the foundations for implementing core control-flow, data, and resource patterns in a distributed workflow environment

    A Lightweight and Attack Resistant Authenticated Routing Protocol for Mobile Adhoc Networks

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    In mobile ad hoc networks, by attacking the corresponding routing protocol, an attacker can easily disturb the operations of the network. For ad hoc networks, till now many secured routing protocols have been proposed which contains some disadvantages. Therefore security in ad hoc networks is a controversial area till now. In this paper, we proposed a Lightweight and Attack Resistant Authenticated Routing Protocol (LARARP) for mobile ad hoc networks. For the route discovery attacks in MANET routing protocols, our protocol gives an effective security. It supports the node to drop the invalid packets earlier by detecting the malicious nodes quickly by verifying the digital signatures of all the intermediate nodes. It punishes the misbehaving nodes by decrementing a credit counter and rewards the well behaving nodes by incrementing the credit counter. Thus it prevents uncompromised nodes from attacking the routes with malicious or compromised nodes. It is also used to prevent the denial-of-service (DoS) attacks. The efficiency and effectiveness of LARARP are verified through the detailed simulation studies.Comment: 14 Pages, IJWM

    Implementation vulnerabilities in general quantum cryptography

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    Quantum cryptography is information-theoretically secure owing to its solid basis in quantum mechanics. However, generally, initial implementations with practical imperfections might open loopholes, allowing an eavesdropper to compromise the security of a quantum cryptographic system. This has been shown to happen for quantum key distribution (QKD). Here we apply experience from implementation security of QKD to several other quantum cryptographic primitives. We survey quantum digital signatures, quantum secret sharing, source-independent quantum random number generation, quantum secure direct communication, and blind quantum computing. We propose how the eavesdropper could in principle exploit the loopholes to violate assumptions in these protocols, breaking their security properties. Applicable countermeasures are also discussed. It is important to consider potential implementation security issues early in protocol design, to shorten the path to future applications.Comment: 13 pages, 8 figure

    KALwEN+: Practical Key Management Schemes for Gossip-Based Wireless Medical Sensor Networks

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    The constrained resources of sensors restrict the design of a key management scheme for wireless sensor networks (WSNs). In this work, we first formalize the security model of ALwEN, which is a gossip-based wireless medical sensor network (WMSN) for ambient assisted living. Our security model considers the node capture, the gossip-based network and the revocation problems, which should be valuable for ALwEN-like applications. Based on Shamir's secret sharing technique, we then propose two key management schemes for ALwEN, namely the KALwEN+ schemes, which are proven with the security properties defined in the security model. The KALwEN+ schemes not only fit ALwEN, but also can be tailored to other scalable wireless sensor networks based on gossiping
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