Abstract
In this poster we describe a work in progress aimed at using a variant of specification-based slicing to improve the reuse of annotated software components, developed under the so called design-by-contract approach. We have named this variant as contract-based because we use the annotations, more precisely the pre and post-conditions, to slice programs intra and inter-procedures. The idea, expressed in the poster, is to take the pre-condition of the reused annotated component as slicing criterion, and slice backward the program where the component is called. In that way, we can isolate the statements that have influence on the variables involved on the pre-condition and check if it is preserved by that invocation, or not. © 2010 IEEE.

Abstract
We apply state-of-the art deductive verification tools to check security-relevant properties of cryptographic software, including safety, absence of error propagation, and correctness with respect to reference implementations. We also develop techniques to help us in our task, focusing on methods oriented towards increased levels of automation, in scenarios where there are clear obvious limits to such automation. These techniques allow us to integrate automatic proof tools with an interactive proof assistant, where the latter is used off-line to prove once-and-for-all fundamental lemmas about properties of programs. The techniques developed have independent interest for practical deductive verification in general. © 2010 Springer-Verlag London Limited.

Abstract
This paper describes a tool-supported method for the formal verification of timed properties of HTL programs, supported by the automated translation tool HTL2XTA, which extracts from a HTL, program (i) an Uppaal model and (ii) a set of properties that state the compliance of the model with certain automatically inferred temporal constraints. These can be manually extended with other temporal properties provided by the user. The paper introduces the details of the proposed mechanisms as well as the results of our experimental validation.

Abstract
In the last years, the concern with the correctness of programs has been leading programmers to enrich their programs with annotations following the principles of design-by-contract, in order to be able to guarantee their correct behaviour and to facilitate reuse of verified components without having to reconstruct proofs of correctness. In this paper we adapt the idea of specification-based slicing to the scope of (contract-based) program verification systems and behaviour specification languages. In this direction, we introduce the notion of contract-based slice of a program and show how any specification-based slicing algorithm can be used as the basis for a contract-based slicing algorithm.

Abstract
We present a case-study of developing a simple software module using contracts, and rigorously verifying it for safety and functional correctness using two very different programming languages, that share the fact that both are extensively used in safety-critical development: SPARK and C/ACSL. This case-study, together with other investigations not detailed here, allows us to establish a comparison in terms of specification effort and degree of automation obtained with each toolset.

Abstract