Sibylle Möhle | Searcharxiv

arXiv2025

Verification of E-Voting Algorithms in Dafny

Electronic voting procedures are implementations of electoral systems, making it possible to conduct polls or elections with the help of computers. This paper reports on the development of an open-source library of electronic voting procedures, which currently covers Score Voting, Instant-Runoff Voting, Borda Count, and Single Transferable Vote. The four procedures, of which two are discussed in detail, have been implemented in Dafny, formally verifying the consistency with functional specifications and key correctness properties. Using code extraction from the Dafny implementation, the library has been used to set up a voting web service.

cs.LO↗

arXiv2024

On Enumerating Short Projected Models

Propositional model enumeration, or All-SAT, is the task to record all models of a propositional formula. It is a key task in software and hardware verification, system engineering, and predicate abstraction, to mention a few. It also provides a means to convert a CNF formula into DNF, which is relevant in circuit design. While in some applications enumerating models multiple times causes no harm, in others avoiding repetitions is crucial. We therefore present two model enumeration algorithms, which adopt dual reasoning in order to shorten the found models. The first method enumerates pairwise contradicting models. Repetitions are avoided by the use of so-called blocking clauses, for which we provide a dual encoding. In our second approach we relax the uniqueness constraint. We present an adaptation of the standard conflict-driven clause learning procedure to support model enumeration without blocking clauses.Our procedures are expressed by means of a calculus and proofs of correctness are provided.

cs.LO↗