355 research outputs found

    I2PA : An Efficient ABC for IoT

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    Internet of Things (IoT) is very attractive because of its promises. However, it brings many challenges, mainly issues about privacy preserving and lightweight cryptography. Many schemes have been designed so far but none of them simultaneously takes into account these aspects. In this paper, we propose an efficient ABC scheme for IoT devices. We use ECC without pairing, blind signing and zero knowledge proof. Our scheme supports block signing, selective disclosure and randomization. It provides data minimization and transactions' unlinkability. Our construction is efficient since smaller key size can be used and computing time can be reduced. As a result, it is a suitable solution for IoT devices characterized by three major constraints namely low energy power, small storage capacity and low computing power

    On the efficiency of revocation in RSA-based anonymous systems

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    © 2016 IEEEThe problem of revocation in anonymous authentication systems is subtle and has motivated a lot of work. One of the preferable solutions consists in maintaining either a whitelist L-W of non-revoked users or a blacklist L-B of revoked users, and then requiring users to additionally prove, when authenticating themselves, that they are in L-W (membership proof) or that they are not in L-B (non-membership proof). Of course, these additional proofs must not break the anonymity properties of the system, so they must be zero-knowledge proofs, revealing nothing about the identity of the users. In this paper, we focus on the RSA-based setting, and we consider the case of non-membership proofs to blacklists L = L-B. The existing solutions for this setting rely on the use of universal dynamic accumulators; the underlying zero-knowledge proofs are bit complicated, and thus their efficiency; although being independent from the size of the blacklist L, seems to be improvable. Peng and Bao already tried to propose simpler and more efficient zero-knowledge proofs for this setting, but we prove in this paper that their protocol is not secure. We fix the problem by designing a new protocol, and formally proving its security properties. We then compare the efficiency of the new zero-knowledge non-membership protocol with that of the protocol, when they are integrated with anonymous authentication systems based on RSA (notably, the IBM product Idemix for anonymous credentials). We discuss for which values of the size k of the blacklist L, one protocol is preferable to the other one, and we propose different ways to combine and implement the two protocols.Postprint (author's final draft

    Assessment of attribute-based credentials for privacy-preserving road traffic services in smart cities

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    Smart cities involve the provision of advanced services for road traffic users. Vehicular ad hoc networks (VANETs) are a promising communication technology in this regard. Preservation of privacy is crucial in these services to foster their acceptance. Previous approaches have mainly focused on PKI-based or ID-based cryptography. However, these works have not fully addressed the minimum information disclosure principle. Thus, questions such as how to prove that a driver is a neighbour of a given zone, without actually disclosing his identity or real address, remain unaddressed. A set of techniques, referred to as Attribute-Based Credentials (ABCs), have been proposed to address this need in traditional computation scenarios. In this paper, we explore the use of ABCs in the vehicular context. For this purpose, we focus on a set of use cases from European Telecommunications Standards Institute (ETSI) Basic Set of Applications, specially appropriate for the early development of smart cities. We assess which ABC techniques are suitable for this scenario, focusing on three representative ones—Idemix, U-Prove and VANET-updated Persiano systems. Our experimental results show that they are feasible in VANETs considering state-of-the-art technologies, and that Idemix is the most promising technique for most of the considered use cases.This work was supported by the MINECO grant TIN2013-46469-R (SPINY: Security and Privacy in the Internet of You); the CAM grant S2013/ICE-3095 (CIBERDINE: Cybersecurity, Data, and Risks) and by the MINECO grant TIN2016-79095-C2-2-R (SMOG-DEV - Security mechanisms for fog computing: advanced security for devices). Jose Maria de Fuentes and Lorena Gonzalez were also supported by the Programa de Ayudas para la Movilidad of Carlos III University of Madrid

    A Decentralised Digital Identity Architecture

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    Current architectures to validate, certify, and manage identity are based on centralised, top-down approaches that rely on trusted authorities and third-party operators. We approach the problem of digital identity starting from a human rights perspective, with a primary focus on identity systems in the developed world. We assert that individual persons must be allowed to manage their personal information in a multitude of different ways in different contexts and that to do so, each individual must be able to create multiple unrelated identities. Therefore, we first define a set of fundamental constraints that digital identity systems must satisfy to preserve and promote privacy as required for individual autonomy. With these constraints in mind, we then propose a decentralised, standards-based approach, using a combination of distributed ledger technology and thoughtful regulation, to facilitate many-to-many relationships among providers of key services. Our proposal for digital identity differs from others in its approach to trust in that we do not seek to bind credentials to each other or to a mutually trusted authority to achieve strong non-transferability. Because the system does not implicitly encourage its users to maintain a single aggregated identity that can potentially be constrained or reconstructed against their interests, individuals and organisations are free to embrace the system and share in its benefits.Comment: 30 pages, 10 figures, 3 table

    Anonymous certification for E-assessment opinion polls

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    Anonymous certification (AC) refers to cryptographic mechanisms in which users get certified from trusted issuers, with regard to some pre-defined user attributes, in order to produce presentation tokens. Such tokens satisfy service providers’ access policies, without revealing sensitive user information. AC systems are generally classified under two main different categories: (1) one-time show credentials that can be shown once for avoiding their originating user being traced from one transaction to another, and (2) multi-show credentials that can be used many times while avoiding their originating user to be traced. In this paper, we consider e-assessment opinion polls scenarios and propose an AC scheme where the one-time show property is relevant for making sure each user cannot hand in more than one poll in order to get significant results. To mitigate cheating, the scheme is provided with two extra procedures: attribute revocation and anonymity removal. The correctness of our scheme, as well as unforgeability, privacy and anonymity removal, are analyzed and demonstrated

    Privacy-preserving PKI design based on group signature

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    Nowadays, Internet becomes a part of our life. We can make use of numerous services with personal computer, Lap-top, tablet, smart phone or smart TV. These devices with network make us enjoy ubiquitous computing life. Sometimes, on-line services request us authentication or identification for access control and authorization, and PKI technology is widely used because of its security. However the possibility of privacy invasion will increase, if We’re identified with same certificate in many services and these identification data are accumulated. For privacy-preserving authentication or anonymous authentication, there have been many researches such as Group signatures, anonymous credentials, etc. Among these researches, group signatures are very practical Because they provide unlinkability and traceability as well as anonymity. In this paper, we propose a privacy-preserving PKI based on group signature, with which users’ privacy can be Kept in services. Because of traceability, their identities can be traced if they abuse anonymity such as cybercrime. Moreover, we will also discuss open issues for further studies
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