ISLearn mines input invariants expressed in the ISLa language that are associated to some program behavior (e.g., “input is accepted”). It is based on a catalog of abstract ISLa patterns that are instantiated and filtered. The resulting invariants are ranked according to their specificity and recall w.r.t. a set of provided or automatically produced input samples.

ISLa (Input Specification Language) is a specification language with a solver for context-sensitive string constraints. Strings are structured using a context-free grammar, and ISLa constraints are expressed in terms of grammar elements. The ISLa solver can report unsatisfiability for unsatisfiable constraints, and generate thousands of sample strings for satisfiable ones. Applications of ISLa include high-precision fuzz testing, debugging based on precise failure circumstances reports, and understanding of program behavior.

REFINITY is a workbench for modeling statement-based program transformation rules using abstract programs, based on Abstract Execution. It provides GUI support for creating models, and sends proof obligations to the KeY program prover to prove correctness of the transformation model. Once created proof certificates can be saved and validated.

The KeY framework is in its core a deduction-based program prover for Java. It is used for research and teaching, and supports functional verification, symbolic debugging, information-flow security, automatic test case generation and more. I have been massively contributing to KeY since 2015. Due to my implementation of Abstract Execution based on KeY, the system can now also prove universal second-order program properties (using abstract programs).