Scaling security in the presence of powerful adversaries – adaptive, coercive and quantum
PhD defence, Tuesday 25th of November, Sebastian Kolby
During his PhD studies, Sebastian Kolby researched cryptographic techniques for building large-scale systems which are secure in the presence of powerful adversaries. In his works he made contributions to YOSO protocols, a class of protocols which scale by delegating work to a small unpredictable subset of parties. Here he contributed towards the first constant round multiparty computation protocols and improved compilers for adaptive security.
Motivated by defending YOSO protocols against coercive adversaries he contributed to the introduction of Deniable Secret Sharing, where shareholders can convincingly lie to an adversary offering a bribe in exchange for the secret, thus preserving the secret. Sebastian also made contributions to aggregate signature schemes, a primitive common to large scale protocols, improving on the previous state-of-the-art post-quantum constructions.
The PhD study was completed at the Department of Computer Science, Faculty of Natural Sciences, Aarhus University.
This summary was prepared by the PhD student.
Time: Tuesday, 25th of November at 13:00
Place: Building 5342, room 333, Department of Computer Science, Aarhus University, Åbogade 34, 8200 Aarhus N
Title of PhD thesis: Studies on Scalable Security
Contact information: Sebastian Kolby, e-mail: sk@cs.au.dk
Members of the assessment committee:
Tenured Researcher Lisa Kohl, Cryptology Group at CWI Amsterdam, Netherlands
Lecturer, Head of Lab Chen-Da Liu-Zhang, Information systems Lab, Blockchain Lab, Lucerne University of Applied Sciences and Arts, Switzerland
Professor Ira Assent (chair), Department of Computer Science, Aarhus University, Denmark
Main supervisor: Associate Professor Sophia Yakoubov, Department of Computer Science, Aarhus University, Denmark
Co-supervisor: Professor Claudio Orlandi, Department of Computer Science, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English
The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C