29,164 research outputs found

    DeV-IP: A k-out-n Decentralized and verifiable BFV for Inner Product evaluation

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    The biometric system has become the desired alternative to a knowledge-based authentication system. An authentication system does not provide uniqueness, as a single user can create multiple registrations with different identities for authentication. Biometric authentication identifies users based on physical traits (fingerprint, iris, face, voice), which allows the system to detect multiple authentications from the same user. The biometric templates must be encrypted or hidden to preserve users\u27 privacy. Moreover, we need a system to perform the matching process over encrypted data without decrypting templates to preserve the users\u27 privacy. For the euclidean distance-based matching process, centralized server-based authentication leads to possible privacy violations of biometric templates since the power of computing inner product value over any two encrypted templates allows the server to retrieve the plain biometric template by computing a few inner products. To prevent this, we considered a decentralized system called collective authority, which is a part of a public network. The collective authority computes the collective public key with contributions from all nodes in the collective authority. It also performs a matching process over encrypted biometric templates in a decentralized manner where each node performs partial matching. Then the leader of the collective authority combines it to get the final value. We further provide a lattice-based verification system for each operation. Every time a node performs some computations, it needs to provide proof of the correctness of the computation, which is publicly verifiable. We finally make the system dynamics using Shamir\u27s secret sharing scheme. In dynamic collective authority, only kk nodes out of the total nn nodes are required to perform the matching process. We further show that the security of the proposed system relies on the security of the underlying encryption scheme and the secret sharing scheme

    Anonymous Single-Sign-On for n designated services with traceability

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    Anonymous Single-Sign-On authentication schemes have been proposed to allow users to access a service protected by a verifier without revealing their identity which has become more important due to the introduction of strong privacy regulations. In this paper we describe a new approach whereby anonymous authentication to different verifiers is achieved via authorisation tags and pseudonyms. The particular innovation of our scheme is authentication can only occur between a user and its designated verifier for a service, and the verification cannot be performed by any other verifier. The benefit of this authentication approach is that it prevents information leakage of a user's service access information, even if the verifiers for these services collude which each other. Our scheme also supports a trusted third party who is authorised to de-anonymise the user and reveal her whole services access information if required. Furthermore, our scheme is lightweight because it does not rely on attribute or policy-based signature schemes to enable access to multiple services. The scheme's security model is given together with a security proof, an implementation and a performance evaluation.Comment: 3

    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

    A Password-Protected Secret Sharing Supporting Multiple Secrets

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    Password-Protected Secret Sharing (PPSS) presented by Bagherzandi et al. is proposed in order to resolve drawback of secret sharing which is unauthorized users can access storages storing partial information can reconstruct a secret. PPSS is a secret sharing that ensures only the owner of the secret who knows correct password to obtain the original secret by applying password authentication to partial information. But, their model requires secure channel between user and servers and independent secret/public key pair at the distribution phase for each secret. When a secret is large, their scheme encrypts the secret with symmetric key encryption (SKE) and the symmetric key with CPA secure public key encryption (PKE).Because of such combination, it seems difficult to prove strong security (i.e., CCA security) of their scheme at least in the standard model. In this paper, we propose a new PPSS model and scheme. Proposed model deals with multiple secrets with using a single secret key/public key pair and does not require secure channel during the distribution phase. Proposed scheme does not use a simple combination of SKE and PKE but use Kurosawa-Desmedt hybrid encryption that is proven to be CCA secure in the standard model, and is constructed by combining public key encryption part of this hybrid encryption with password authentication.The scheme is expected to be more secure than that of Bagherzandi et al
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