Abstract-An attacker that can identify messages as coming from the same source, can use this information to build up a picture of targets' behaviour, and so, threaten their privacy. In response to this danger, unlinkable protocols aim to make it impossible for a third party to identify two runs of a protocol as coming from the same device. We present a framework for analysing unlinkability and anonymity in the applied pi calculus. We show that unlinkability and anonymity are complementary properties; one does not imply the other. Using our framework we show that the French RFID e-passport preserves anonymity but it is linkable therefore anyone carrying a French e-passport can be physically traced.

No abstract

Abstract-We present StatVerif, which is an extension the ProVerif process calculus with constructs for explicit state, in order to be able to reason about protocols that manipulate global state. Global state is required by protocols used in hardware devices (such as smart cards and the TPM), as well as by protocols involving databases that store persistent information. We provide the operational semantics of StatVerif. We extend the ProVerif compiler to a compiler for StatVerif: it takes processes written in the extended process language, and produces Horn clauses. Our compilation is carefully engineered to avoid many false attacks. We prove the correctness of the StatVerif compiler. We illustrate our method on two examples: a small hardware security device, and a contract signing protocol. We are able to prove their desired properties automatically.

Abstract-We present StatVerif, which is an extension the ProVerif process calculus with constructs for explicit state, in order to be able to reason about protocols that manipulate global state. Global state is required by protocols used in hardware devices (such as smart cards and the TPM), as well as by protocols involving databases that store persistent information. We provide the operational semantics of StatVerif. We extend the ProVerif compiler to a compiler for StatVerif: it takes processes written in the extended process language, and produces Horn clauses. Our compilation is carefully engineered to avoid many false attacks. We prove the correctness of the StatVerif compiler. We illustrate our method on two examples: a small hardware security device, and a contract signing protocol. We are able to prove their desired properties automatically.

Abstract. Will my vote remain secret in 20 years? This is a natural question in the context of electronic voting, where encrypted votes may be published on a bulletin board for verifiability purposes, but the strength of the encryption is eroded with the passage of time. The question has been addressed through a property referred to as everlasting privacy. Perfect everlasting privacy may be difficult or even impossible to achieve, in particular in remote electronic elections. In this paper, we propose a definition of practical everlasting privacy. The key idea is that in the future, an attacker will be more powerful in terms of computation (he may be able to break the cryptography) but less powerful in terms of the data he can operate on (transactions between a vote client and the vote server may not have been stored).We formalize our definition of everlasting privacy in the applied-pi calculus. We provide the means to characterize what an attacker can break in the future in several cases. In particular, we model this for perfectly hiding and computationally binding primitives (or the converse), such as Pedersen commitments, and for symmetric and asymmetric encryption primitives. We adapt existing tools, in order to allow us to automatically prove everlasting privacy. As an illustration, we show that several variants of Helios (including Helios with Pedersen commitments) and a protocol by Moran and Naor achieve practical everlasting privacy, using the ProVerif and the AKiSs tools.