I2PA : An Efficient ABC for IoT

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

Maintaining unlinkability in group based P2P environments

In the wake of the success of Peer-to-Peer (P2P) networking, security has arisen as one of its main concerns, becoming a key issue when evaluating a P2P system. Unfortunately, some systems' design focus targeted issues such as scalabil-ity or overall performance, but not security. As a result, security mechanisms must be provided at a later stage, after the system has already been designed and partially (or even fully) implemented, which may prove a cumbersome proposition. This work exposes how a security layer was provided under such circumstances for a specic Java based P2P framework: JXTA-Overlay.Arran de l'èxit de (P2P) peer-to-peer, la seguretat ha sorgit com una de les seves principals preocupacions, esdevenint una qüestió clau en l'avaluació d'un sistema P2P. Malauradament, alguns sistemes de disseny apunten focus de problemes com l'escalabilitat o l'acompliment general, però no de seguretat. Com a resultat d'això, els mecanismes de seguretat s¿han de proporcionar en una etapa posterior, després que el sistema ja ha estat dissenyat i parcialment (o fins i tot totalment) implementat, la qual cosa pot ser una proposició incòmode. Aquest article exposa com es va proveir una capa de seguretat sota aquestes circumstàncies per un Java específic basat en un marc P2P: JXTA-superposició.A raíz del éxito de (P2P) peer-to-peer, la seguridad ha surgido como una de sus principales preocupaciones, convirtiéndose en una cuestión clave en la evaluación de un sistema P2P. Desgraciadamente, algunos sistemas de diseño apuntan un foco de problemas como la escalabilidad o el desempeño general, pero no de seguridad. Como resultado de ello, los mecanismos de seguridad se proporcionarán en una etapa posterior, después de que el sistema ya ha sido diseñado y parcialmente (o incluso totalmente) implementado, lo que puede ser una proposición incómodo. Este artículo expone cómo se proveyó una capa de seguridad bajo estas circunstancias por un Java específico basado en un marco P2P: JXTA-superposición

A-MAKE: an efficient, anonymous and accountable authentication framework for WMNs

In this paper, we propose a framework, named as A-MAKE, which efficiently provides security, privacy, and accountability for communications in wireless mesh networks. More specifically, the framework provides an anonymous mutual authentication protocol whereby legitimate users can connect to network from anywhere without being identified or tracked. No single party (e.g., network operator) can violate the privacy of a user, which is provided in our framework in the strongest sense. Our framework utilizes group signatures, where the private key and the credentials of the users are generated through a secure three-party protocol. User accountability is implemented via user revocation protocol that can be executed by two semitrusted authorities, one of which is the network operator. The assumptions about the trust level of the network operator are relaxed. Our framework makes use of much more efficient signature generation and verification algorithms in terms of computation complexity than their counterparts in literature, where signature size is comparable to the shortest signatures proposed for similar purposes so far

Security, privacy and trust in wireless mesh networks

With the advent of public key cryptography, digital signature schemes have been extensively studied in order to minimize the signature sizes and to accelerate their execution while providing necessary security properties. Due to the privacy concerns pertaining to the usage of digital signatures in authentication schemes, privacy-preserving signature schemes, which provide anonymity of the signer, have attracted substantial interest in research community. Group signature algorithms, where a group member is able to sign on behalf of the group anonymously, play an important role in many privacy-preserving authentication/ identification schemes. On the other hand, a safeguard is needed to hold users accountable for malicious behavior. To this end, a designated opening/revocation manager is introduced to open a given anonymous signature to reveal the identity of the user. If the identified user is indeed responsible for malicious activities, then s/he can also be revoked by the same entity. A related scheme named direct anonymous attestation is proposed for attesting the legitimacy of a trusted computing platform while maintaining its privacy. This dissertation studies the group signature and direct anonymous attestation schemes and their application to wireless mesh networks comprising resource-constrained embedded devices that are required to communicate securely and be authenticated anonymously, while malicious behavior needs to be traced to its origin. Privacy-aware devices that anonymously connect to wireless mesh networks also need to secure their communication via efficient symmetric key cryptography, as well. In this dissertation, we propose an efficient, anonymous and accountable mutual authentication and key agreement protocol applicable to wireless mesh networks. The proposed scheme can easily be adapted to other wireless networks. The proposed scheme is implemented and simulated using cryptographic libraries and simulators that are widely deployed in academic circles. The implementation and simulation results demonstrate that the proposed scheme is effective, efficient and feasible in the context of hybrid wireless mesh networks, where users can also act as relaying agents. The primary contribution of this thesis is a novel privacy-preserving anonymous authentication scheme consisting of a set of protocols designed to reconcile user privacy and accountability in an efficient and scalable manner in the same framework. The three-party join protocol, where a user can connect anonymously to the wireless mesh network with the help of two semi-trusted parties (comprising the network operator and a third party), is efficient and easily applicable in wireless networks settings. Furthermore, two other protocols, namely two-party identification and revocation protocols enable the network operator, with the help of the semi-trusted third party, to trace suspected malicious behavior back to its origins and revoke users when necessary. The last two protocols can only be executed when the two semi-trusted parties cooperate to provide accountability. Therefore, the scheme is protected against an omni-present authority (e.g. network operator) violating the privacy of network users at will. We also provide arguments and discussions for security and privacy of the proposed scheme

On the efficiency of revocation in RSA-based anonymous systems

© 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