© Universität Siegen

Bernhard Esslinger (bernhard.esslinger@uni-siegen.de) 
Professor Cryptology and IT Security 

Former head of the CrypTool project (www.cryptool.org) 
Former CISO and development head at SAP; former head IT security at Deutsche Bank 

Staff: colleagues and their core areas:

• Maik Bastian: researcher, combining cryptanalysis and machine learning (artificial intelligence)

Latest books:

• https://www.lehmanns.de/shop/mathematik-informatik/82388950-9783965436107-kryptografie-lernen-und-anwenden-mit-cryptool-und-sagemath
• https://www.cryptool.org/en/ctbook/

Offerings for students (as of November 2025):

• Students interested in cryptology, didactics, UX, and participation in international open-source projects in the area of cryptology are always welcome doing their bachelor and master projects, or their bachelor and master thesis with us.
• A selection of some good former examples (titles and completed reports) can be found here: 
  https://www.cryptool.org/en/publications/
• We practice a close relationship to the computer science department in faculty IV of the University of Siegen and to several chairs at other universities in Germany and abroad.
• We are well known for supervising our students with great care but also with high expectations. In participating in open-source projects they learn to deepen and apply the theoretical methods, and they experience how modern distributed and agile project work goes on.
• We have several open projects and thesis topics (Abschlussarbeiten und Projekte). Please send us an email.