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Seminar: Abstract cryptography

Dr. Christopher Portmann
(ETH Zürich)

Dr. Christopher Portmann of the Institute for Theoretical Physics at ETH Zürich, Switzerland, will be speaking on "Abstract cryptography". The seminar will be presented by the Institute for Quantum Computing and held in QNC 1201 at the University of Waterloo.

Seminar abstract:

"Cryptography (AC) is a composable security framework by Maurer and Renner, which generalizes previous frameworks, e.g. Canetti's Universal Composability (UC). By defining security on a level of abstraction where the underlying computational model has not been specified, it applies seamlessly to both classical and quantum cryptography. One of the main contributions of AC - apart from simplifying the security model - is that it allows multiple non-cooperating dishonest players to be directly modeled, e.g. coercibility.

This talk will be an introduction to (quantum) AC, with focus on the novelties of this framework. In particular, I will talk about some current research with Renato Renner, in which we are defining the security of device independent protocols by modeling the quantum devices as dishonest players.

I will use the occasion to dispel two common misconceptions about composable security. The first is that defining composable security is complicated; with AC it is actually straightforward. The second is that using a composable framework leads mostly to impossibility results. I will explain how, by explicitly modeling the (hidden) assumptions of stand-alone security, stand-alone protocols can (and should) be proven secure in a composable framework."