Modern cryptography in theory and practice

Dr Stefan Tillich
Department of Computer Science, University of Bristol

Date: 22nd February 2011 (Tuesday)
Time: 14:00 - 15:00
Venue: MB504

Traditionally, theory and practice in cryptography have been more or less separate domains, linked together by common assumptions. Theory has been regarded as a purely mathematical and information-theoretic domain, treating cryptographic primitives as impenetrable black boxes (black- box cryptography). On the other hand, practical implementations of cryptographic systems were left to engineers. As a consequence, many security systems turned out to be insecure in practice due to misconceptions of either their designers or their implementers. The perhaps most famous example is the break of the German Enigma cipher machine in World War 2, which contributed significantly to the Allied victory. As a consequence, the “linking” assumptions between theory and practice have been increasingly perceived as being unrealistic for many modern applications. Thus, theory and practice have become increasingly intertwined in the last decades. Attempts at unification have been made from both the practical side (e.g. implementation attack countermeasures) as well as the theoretical side (e.g. leakage-resilient cryptography, white-box cryptography). The speaker has worked in the field of practical cryptography for several years, investigating efficient and secure software and hardware implementations for various devices. The focal points of his research were instruction set extensions for cryptography as well as implementation attack techniques and countermeasures. In light of the speaker’s practical experience in cryptography research, this talk covers both the basics of modern theoretic and practical cryptography, in particular the design of cryptographic primitives and protocols using security proofs as well as the threat of implementation attacks.