5,475 research outputs found

    On Selecting the Nonce Length in Distance-Bounding Protocols

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    Distance-bounding protocols form a family of challenge-response authentication protocols that have been introduced to thwart relay attacks. They enable a verifier to authenticate and to establish an upper bound on the physical distance to an untrusted prover. We provide a detailed security analysis of a family of such protocols. More precisely, we show that the secret key shared between the verifier and the prover can be leaked after a number of nonce repetitions. The leakage probability, while exponentially decreasing with the nonce length, is only weakly dependent on the key length. Our main contribution is a high probability bound on the number of sessions required for the attacker to discover the secret, and an experimental analysis of the attack under noisy conditions. Both of these show that the attack's success probability mainly depends on the length of the used nonces rather than the length of the shared secret key. The theoretical bound could be used by practitioners to appropriately select their security parameters. While longer nonces can guard against this type of attack, we provide a possible countermeasure which successfully combats these attacks even when short nonces are use

    Compartmentation policies for Android apps:A combinatorial optimization approach

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    Some smartphone platforms such as Android have a distinctive message passing system that allows for sophisticated interactions among app components, both within and across app boundaries. This gives rise to various security and privacy risks, including not only intentional collusion attacks via permission re-delegation but also inadvertent disclosure of information and service misuse through confused deputy attacks. In this paper, we revisit the perils of app coexistence in the same platform and propose a risk mitigation mechanism based on segregating apps into isolated groups following classical security compartmentation principles. Compartments can be implemented using lightweight approaches such as Inter-Component Communication (ICC) firewalling or through virtualization, effectively fencing off each group of apps. We then leverage recent works on quantified risk metrics for Android apps to couch compartmentation as a combinatorial optimization problem akin to the classical bin packing or knapsack problems. We study a number of simple yet effective numerical optimization heuristics, showing that very good compartmentation solutions can be obtained for the problem sizes expected in current’s mobile environments

    SLRV: An RFID Mutual Authentication Protocol Conforming to EPC Generation-2 Standard

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    Having done an analysis on the security vulnerabilities of Radio Frequency Identification (RFID) through a desynchronization and an impersonation attacks, it is revealed that the secret information (i.e.: secret key and static identifier) shared between the tag and the reader is unnecessary. To overcome the vulnerability, this paper introduces Shelled Lightweight Random Value (SLRV) protocol; a mutual authentication protocol with high-security potentials conforming to  electronic product code (EPC) Class-1 Generation-2 Tags, based on lightweight and standard cryptography on the tag’s and reader’s side, respectively. SLRV prunes de-synchronization attacks where the updating of internal values is only executed on the tag’s side and is a condition to a successful mutual authentication. Results of security analysis of SLRV, and comparison with existing protocols, are presented
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