The theory group pursues research in four areas: information security and cryptography, logic (in computer science), automata theory (and formal languages)., and computer science education.

## Information Security and Cryptography

Information Security and Cryptography are disciplines in computer science that provides techniques for making digital communication secure and protecting information in general. Applications range from secure channels in computer networks to digital rights management. The theory group’s objective is to develop rigorous, general notions and models of security, to advance their theory, and to develop methods and tools for analyzing cryptographic protocols.

## Logics

Logics are the perfect mathematical tool for specifying properties or relations and are used in many different areas of computer science, for instance, temporal logics are used for specifying properties of reactive systems and first-order logic is used as a model query language in database theory. The theory group investigates the expressiveness and algorithmic properties of temporal, knowledge-based, and description logics.

## Automata

Automata are one of the most fundamental and versatile mathematical concepts of computer science. A rich mathematical theory makes them applicable in various areas such as verification and compiler construction. The theory group develops the mathematical theory of automata, often using algebraic techniques and aiming at answering questions in verification.

## Complexity Theory and Algorithms

In Complexity theory computational problems are classified according to required ressources like time and memory space for algorithms that solve these problems. With that different problems can be compared and classfied into several complexity classes, which may yield us complete complexity hierarchies.

In our group we study parallel, parameterized and optimization problems and develop algorithms for them.

## Publications

For the publications on all the topics, please, check out the individual home pages of the members of the group.