In wireless systems, the communication mechanism combines features of broadcast, synchrony, and asynchrony. We develop an operational semantics for a calculus of wireless systems. We present a Reduction Semantics and a Labelled Transition Semantics and prove a correspondence result between them. We first consider a core calculus, essentially with only the primitives for communication, and then a few extensions. A major goal of the semantics is to describe the forms of interferences among the activities of processes that are peculiar of wireless systems. Such interferences occur when a location is simultaneously reached by two transmissions.

Abstract. We present the ω-calculus, a process calculus for formally modeling and reasoning about Mobile Ad Hoc Wireless Networks (MANETs) and their protocols. The ω-calculus naturally captures essential characteristics of MANETs, including the ability of a MANET node to broadcast a message to any other node within its physical transmission range (and no others), and to move in and out of the transmission range of other nodes in the network. A key feature of the ω-calculus is the separation of a node’s communication and computational behavior, described by an ω-process, from the description of its physical transmission range, referred to as an ω-process interface. Our main technical results are as follows. We give a formal operational semantics of the ω-calculus in terms of labeled transition systems and show that the state reachability problem is decidable for finite-control ω-processes. We also prove that the ω-calculus is a conservative extension of the π-calculus, and that late bisimulation (appropriately lifted from the π-calculus to the ω-calculus) is a congruence. Congruence results are also established for a weak version of late bisimulation, which abstracts away from two types of internal actions: τ-actions, as in the π-calculus, and µ-actions, signaling node movement. Finally, we illustrate the practical utility of the calculus by developing and analyzing a formal model of a leader-election protocol for MANETs. 1

Wireless communication enables a broad spectrum of applications, ranging from commodity to tactical systems. Neighbor discovery (ND), that is, determining which devices are within direct radio communication, is a building block of network protocols and applications, and its vulnerability can severely compromise their functionalities. A number of proposals to secure ND have been published, but none have analyzed the problem formally. In this paper, we contribute such an analysis: We build a formal model capturing salient characteristics of wireless systems, most notably obstacles and interference, and we provide a specification of a basic variant of the ND problem. Then, we derive an impossibility result for a general class of protocols we term “time-based protocols,” to which many of the schemes in the literature belong. We also identify the conditions under which the impossibility result is lifted. Moreover, we explore a second class of protocols we term “time- and location-based protocols,” and prove they can secure ND.

Abstract. Mobile ad hoc networks consist of mobile wireless devices which autonomously organize their infrastructure. In such a network, a central issue, ensured by routing protocols, is to find a route from one device to another. Those protocols use cryptographic mechanisms in order to prevent a malicious node from compromising the discovered route. We present a calculus for modeling and reasoning about security protocols, including in particular secured routing protocols. Our calculus extends standard symbolic models to take into account the characteristics of routing protocols and to model wireless communication in a more accurate way. Then, by using constraint solving techniques, we propose a decision procedure for analyzing routing protocols for a bounded number of sessions and for a fixed network topology. We demonstrate the usage and usefulness of our approach by analyzing the protocol SRP applied to DSR. 1

In wireless systems, neighbor discovery (ND) is a fundamental building block: determining which devices are within direct radio communication is an enabler for networking protocols and a wide range of applications. To thwart abuse of ND and the resultant compromise of the dependent functionality of wireless systems, numerous works proposed solutions to secure ND. Nonetheless, until very recently, there has been no formal analysis of secure ND protocols. We close this gap in [24], but we concentrate primarily on the derivation of an impossibility result for a class of protocols. In this paper, we focus on reasoning about specific protocols. First, we contribute a number of extensions and refinements on the framework of [24]. As we are particularly concerned with the practicality of provably secure ND protocols, we investigate availability and redefine accordingly the ND specification, and also consider composability of ND with other protocols. Then, we propose and analyze two secure ND protocols: We revisit one of the protocols analyzed in [24], and introduce and prove correct a more elaborate challenge-response protocol.

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Abstract. In protocol development for wireless systems, the choice of appropriate mobility models describing the movement patterns of devices has long been recognised as a crucial factor for the successful evaluation of protocols. More recently, wireless protocols have also come into the focus of formal approaches to the modelling and verification of concurrent systems. While in these approaches mobility is also given a central role, the actual mobility modelling remains simplistic since arbitrary node movements are allowed. This leads to a huge behavioural overapproximation that might prevent a successful reasoning about protocol properties. In this paper we describe how to extend a process calculus by realistic mobility models in an orthogonal way. The semantics of our calculus incorporates a notion of global time passing that allows us to express a wide range of mobility models currently used in protocol development practice. Using the behavioural equivalence and pre-order of our calculus, we are furthermore able to compare the strength of these models in our approach. 1

Psi-calculi is a parametric framework for extensions of the pi-calculus, with arbitrary data structures and logical assertions for facts about data. This thesis presents broadcast psi-calculi and higher-order psi-calculi, two extensions of the psi-calculi framework, allowing respectively one-to-many communications and the use of higher-order process descriptions through conditions in the parameterised logic. Both extensions preserve the purity of the psi-calculi semantics; the standard congruence and structural properties of bisimilarity are proved formally in Isabelle. The work going into the extensions show that depending on the specific extension, working out the formal proofs can be a work-intensive process. We find that some of this work could be automated, and implementing such automation may facilitate the development of future extensions to the psi-calculi framework. Acknowledgements I would like to thank my advisor, Joachim Parrow, and my co-advisor, Björn Victor for all their support, help, and advice. I would like to thank all the co-authors; Johannes Borgström, Shuqin Huang,