Regression verification is an approach complementing regression testing with formal verification. The goal is to formally prove that two versions of a program behave either equally or differently in a precisely specified way. In this paper, we present a novel automatic approach for regression verification that reduces the equivalence of two related imperative integer programs to Horn constraints over uninterpreted predicates. Subsequently, state-of-the-art SMT solvers are used to solve the constraints. We have implemented the approach, and our experiments show non-trivial integer programs that can now be proved equivalent without further user input.

The KeY system offers a platform of software analysis tools for sequential Java. Foremost, this includes full functional verification against contracts written in the Java Modeling Language. But the approach is general enough to provide a basis for other methods and purposes: (i) complementary validation techniques to formal verification such as testing and debugging, (ii) methods that reduce the complexity of verification such as modularization and abstract interpretation, (iii) analyses of non-functional properties such as information flow security, and (iv) sound program transformation and code generation. We show that deductive technology that has been developed for full functional verification can be used as a basis and framework for other purposes than pure functional verification. We use the current release of the KeY system as an example to explain and prove this claim.

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It is a common belief that the rise of standardized software certification schemes like the Common Criteria (CC) would give a boost to formal verification, and that software certification may be a killer application for program verification. However, while formal models are indeed used throughout high-assurance certification, verification of the actual implementation is not required by the CC and largely neglected in certification practicedespite the great advances in program verification over the last decade.In this paper we discuss the gap between program verification and CC software certification, and we point out possible uses of code-level program verification in the CC certification process.