This is the homepage of the research group "Cryptography and Complexity Theory" (Cryptoplexity). The group has been established in July 2011 at the Technische Universität Darmstadt as a Heisenberg-Professorship of the German Research Foundation DFG and has been supported through that program till June 2016 (see Projects: Heisenberg for more information).

Research Area

Our research area is complexity-based cryptography which investigates the relationship of (abstract or concrete) cryptographic problems, such as the security of complex cryptographic protocols built out of more fundamental cryptographic primitives. Our security proofs for the protocols of the new German identity card are a concrete example for our work.

Central to our research are the question of modelling (what does it mean to be secure?) and the notion of a reduction, originating from complexity theory and nowadays forming the common technique to conduct security proofs. We are interested in both the applications of these notions as well as the notions as a research topic themselves. This requires vivid interaction with related areas like complexity theory, IT security, number theory, or algorithmics.


We view ourselves as a research-oriented group which, in collaboration with national and international partners from research, industry and the public sector, enhances the areas of cryptography and IT security. Our actions are based on the Rules of Good Scientific Practice, as described for example by the German Research Foundation (DFG). And we're fun.


Visitor's Address: S2|20, 1st Floor, Pankratiusstraße 2, D-64289 Darmstadt, Germany

Postal Address: Cryptoplexity | Computer Science | TU Darmstadt | Pankratiusstraße 2 | D-64289 Darmstadt | Germany

Phone: +49-6151-16-22486

Fax: +49-6151-16-22487


For all other matters please contact Andrea Püchner.