ProvSec

 

Jens Groth.jpg 

Title: A Classification of Non-interactive Assumptions in Cyclic Groups

 

Prof. Jens Groth

Department of Computer Science, University College London, UK

URL: http://www0.cs.ucl.ac.uk/staff/J.Groth/

Abstract:

In the provable security paradigm, we gain confidence in the security of a cryptographic scheme by giving a proof that compromising security corresponds to breaking an underlying intractability assumption. As a rule of thumb, the more cryptanalytic study an intractability assumption has been able to resist, the more confident we are that it holds. However, many assumptions have been proposed that have never received much cryptanalytic attention. In particular, in the world of pairing-based cryptography there exists a wilderness of assumptions.

In this talk, we will take initial steps towards organizing the landscape of assumptions. We will in particular focus on the case of non-interactive assumptions in cyclic groups and show that the assumptions can be organized into a hierarchy. For cryptographers this means schemes can be based on a well-organized set of assumptions, for cryptanalysts this means we can identify central intractability assumptions worth scrutinizing.

Short Bio:

Jens Groth received his PhD in Computer Science from Aarhus University in Denmark. Afterwards he did a Post-Doc at University of California Los Angeles, where he received the 2007 UCLA Chancellor's Award for Postdoctoral Research. He is now Professor of Cryptology in the Department of Computer Science at University College London and the Director of UCL's Academic Centre of Excellence in Cyber Security Research. His research interests include electronic voting, anonymization protocols, advanced digital signatures, public-key encryption and zero-knowledge proofs. He is among the 20 most published authors worldwide at the top cryptology conferences ASIACRYPT, EUROCRYPT and CRYPTO over the last decade.



Jens Groth.jpg 

Title: Modelling the Security of Key Exchange

 

Prof. Prof. Colin Boyd

Department of Telematics, Norwegian University of Science and Technology, Norway

URL: https://www.ntnu.edu/employees/colinab

Abstract:

At the first ProvSec conference in 2007 a new model for secure key exchange was quietly introduced in a paper of LaMacchia, Lauter and Mityagin. Since then this model, known as the eCK model, has become widely used and the paper cited over 400 times. There have been many refinements and adjustments to the eCK model and quite a lot of controversy regarding its relation to other models and how best to satisfy security within it.

However, for modeling of real-world protocols, most prominently TLS, the eCK model has had little influence. Indeed, real-world protocols tend to be insecure in such models. At the same time, provable security of key exchange has been widely applied recently to real-world protocols, including retrospective analysis of TLS 1.2 (and earlier) and design-oriented analysis for TLS 1.3. This has required more complex models to capture issues such as negotiation of versions and primitives, usage of multiple ciphersuites, security of sessions, renewal of related protocol sessions, and weaker initial keys.

This talk aims to provide an overview of provable security key exchange models explaining the above developments. The talk will include a historical perspective, a look at current trends, and some speculation about the future.

Short Bio:

Colin Boyd is a professor of information security at the Norwegian University of Science and Technology (NTNU). Prior to moving to Norway in 2013, he was professor at Queensland University of Technology where he contributed to research and teaching for almost 18 years. His earlier professional experience was at University of Manchester and British Telecom Research Labs. Trained as a mathematician, Colin has had a fascination with cryptography for 30 years, with a particular interest in key exchange protocols.






2015-2016 All Rights Rreserved.