Title:  Constructive Cryptography (and more)

Abstract:

This interactive presentation consists of several parts, including:

1)      A simple abstract resource theory, where resources are elements of a partially ordered set and where ajoining resources, relaxations of resources, and constructions (of resources from resources), are captured as order-preserving functions (i.e., as homomorphisms) satisfying certain axioms, for example (one-sided) commutativity of certain homomorphisms.

2)      A theory of discrete probabilistic systems, where most systems discussed in cryptography (and beyond) can be understood as descriptions (in a particular language, for example a specific pseudo-code language) of such discrete systems. An instantiation of discrete systems for modeling time is also discussed, which is important for modeling guarantees in asynchronous systems such as blockchain systems.

3)      Constructive cryptography as an instantiation of the resource theory, where resources are (specifications, i.e., sets of) discrete systems. Many diverse types of traditional statements in cryptography can benaturally unified and seen as being of the same type, for example information-theoretic and cryptographic security, static and adaptive corruption, and synchronous and asynchronous models as well as models capturing time. 

If time permits, I will also discuss an abstract theory of reductions that requires no computational model but nevertheless allows to capture typical complexity-based statements in cryptography (and beyond).

The presentation is targeted at two different audiences, cryptographers and formal method specialists, and it aims at providing a bridge between them to allow cryptographers to make clean security statements that are formalizable and amenable to machine-checkable proofs. But the presented framework has a wider scope than cryptography; the ultimate goal (not yet worked out) is to capture statements at various levels, from the physical layer over digital circuits and software to the application, with cryptographic statements naturally integrated, as construction steps in a single framework. Based partially on joint work with Renato Renner and with many other researchers.

About the speaker: Professor Ueli Maurer is Professor of Computer Science at ETH Zürich https://www.crypto.ethz.ch/~maurer/

About the presentation: The presentation is open to everyone and is organized by the Concordium Blockchain Research Centre Aarhus - For further information about the research centre please visit the centre website: http://cs.au.dk/research/centers/concordium/