My research area is complexity-based cyptography 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. The security proofs for the protocols of the new German identity card are a concrete example for my work.
Central to my research is 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 for protocols. I'm 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.