Victor Shoup	
New York University

GNUC: A New Universal Composability Framework

We put forward a framework for the modular design and analysis of multi-party protocols.
Our framework is called "GNUC" (with the recursive meaning "GNUC's Not UC"), already
alluding to the similarity to Canetti's Universal Composability (UC) framework. In particular,
like UC, we offer a universal composition theorem, as well as a theorem for composing protocols
with joint state.

We deviate from UC in several important aspects. Specically, we have a rather different
view than UC on the structuring of protocols, on the notion of polynomial-time protocols and
attacks, and on corruptions. We will motivate our definitional choices by explaining why the
definitions in the UC framework are problematic, and how we overcome these problems.

Our goal is to make offer a framework that is largely compatible with UC, such that previous
results formulated in UC carry over to GNUC with minimal changes. We exemplify this by giving
explicit formulations for several important protocol tasks, including authenticated and secure
communication, as well as commitment and secure function evaluation.

Joint work with Dennis Hofheinz.