Quantum logic in dagger kernel categories

This paper investigates quantum logic from the perspective of categorical logic, and starts from minimal assumptions, namely the existence of involutions/daggers and kernels. The resulting structures turn out to (1) encompass many examples of interest, such as categories of relations, partial injections, Hilbert spaces (also modulo phase), and Boolean algebras, and (2) have interesting categorical/logical properties, in terms of kernel fibrations, such as existence of pullbacks, factorisation, and orthomodularity. For instance, the Sasaki hook and and-then connectives are obtained, as adjoints, via the existential-pullback adjunction between fibres

Biometrics and their use in e-passports

A successful design, deployment and operation of biometric systems depends highly on the results for existing biometrical technologies and components. These existing technologies as well as new solutions need to be evaluated on their performance. However it is often forgotten that the biometric (iris, finger, face e.g.) is only one part of a fully deployed application. As biometric (sub)systems are often not designed with security and or privacy in mind, system integrators will need to address the requirements of the deployed application in this light. The fears and concerns of a significant segment of the user population need to be addressed as early as possible in the design process, to ensure that appropriate mechanisms are in place to reassure such users. These concerns may relate to privacy or to safety issues, which may be addressed in part through legal and regulatory measures. This article discusses the requirements, design and application scenario’s of biometrical systems in general and the introduction of a new biometrical passport in The Netherlands in particular. On the one hand it is based on one of the authors’ (BS) lecture notes of the Second International Summer School on Biometrics for Secure Authentication , Alghero (IT), Summer 2005 (The summer school is co-organized by the BioSecure network of Excellence in Biometrics and supported by the European Biometrics Forum). On the other hand it is based on the other authors’ (BJ) experiences as external advisor of the Ministry of Internal Affairs in The Netherlands – which is responsible for the introduction of the new passport

Simulations in coalgebra

A new approach to simulations is proposed within the theory of coalgebras by taking a notion of order on a functor as primitive. Such an order forms a basic buildingblock for a lax relation lifting , or relator as used by other authors. Simulations appear as coalgebras of this lifted functor, and similarity as greatest simulation. Two-way similarity is then similarity in both directions. In general, it is different from bisimilarity (in the usual coalgebraic sense), but a sufficient condition is formulated (and illustrated) to ensure that bisimilarity and two-way similarity coincide. Also, suitable conditions are identified which ensures that similarity on a final coalgebra forms an (algebraic) dcpo structure. This involves a close investigation of the iterated applications Fn(Ø) and Fn(1) of a functor F with an order to the initial algebras and final objects

Modular termination verification of single-threaded and multithreaded programs

\u3cp\u3eWe propose an approach for the modular specification and verification of total correctness properties of object-oriented programs. The core of our approach is a specification style that prescribes a way to assign a level expression to each method such that each callee's level is below the caller's, even in the presence of dynamic binding. The specification style yields specifications that properly hide implementation details. The main idea is to use multisets of method names as levels, and to associate with each object levels that abstractly reflect the way the object is built from other objects. A method's level is then defined in terms of the method's own name and the levels associated with the objects passed as arguments. We first present the specification style in the context of programs that do not modify object fields.We then combine it with separation logic and abstract predicate families to obtain an approach for programs with heap mutation. In a third step, we address concurrency, by incorporating an existing approach for verifying deadlock freedom of channels and locks. Our main contribution here is to achieve information hiding by using the proposed termination levels for lock ordering as well. Also, we introduce call permissions to enable elegant verification of termination of programs where threads cause work in other threads, such as in thread pools or fine-grained concurrent algorithms involving compare-and-swap loops. We explain how our approach can be used also to verify the liveness of nonterminating programs.\u3c/p\u3

Crossing borders: Security and privacy issues of the European e-passport

The first generation of European e-passports will be issued in 2006. We discuss how borders are crossed regarding the security and privacy erosion of the proposed schemes, and show which borders need to be crossed to improve the security and the privacy protection of the next generation of e-passports. In particular we discuss attacks on Basic Access Control due to the low entropy of the data from which the access keys are derived, we sketch the European proposals for Extended Access Control and the weaknesses in that scheme, and show how fundamentally different design decisions can make e-passports more secure

Verifying atomicity preservation and deadlock freedom of a generic shared variable mechanism used in model-to-code transformations

\u3cp\u3eA challenging aspect of model-to-code transformations is to ensure that the semantic behavior of the input model is preserved in the output code. When constructing concurrent systems, this is mainly difficult due to the non-deterministic potential interaction between threads. In this paper, we consider this issue for a framework that implements a transformation chain from models expressed in the state machine based domain specific language SLCO to Java. In particular, we provide a fine-grained generic mechanism to preserve atomicity of SLCO statements in the Java implementation. We give its generic specification based on separation logic and verify it using the verification tool VeriFast. The solution can be regarded as a reusable module to safely implement atomic operations in concurrent systems. Moreover, we also prove with VeriFast that our mechanism does not introduce deadlocks. The specification formally ensures that the locks are not reentrant which simplifies the formal treatment of the Java locks.\u3c/p\u3