Cryptographic Tools for Auditability Purposes

PhD Qualifying Examination


Title: "Cryptographic Tools for Auditability Purposes"

by

Mr. Vlasios KOUTSOS


Abstract:

Auditability in the sense of the ability (i) to compute a function output on 
data and (ii) to verify the output correctness is a crucial property in 
multiple real-world systems. However, this property is far from trivial to 
achieve in most cases and especially when the auditor is different from both 
the data owner and the entity who performs the functional evaluation. We 
observe that depending on the application, various definitions or flavors of 
auditability have been proposed over the years, satisfying different aspects of 
security and privacy. Specifically, a plethora of cryptographic components have 
been developed and used to enable or incorporate auditability features. The 
addition of such components while ensuring desirable properties usually come 
with a performance overhead. In this literature review, we define and explain 
the model of interaction and security for verifying computations over data. We 
review the most relevant and important research directions and approaches in 
the area. We categorize existing solutions according to the setting they 
operate in, namely a 2-entity or a 3-entity one. In the former case the data 
owner and the auditor are usually the same entity. We identify that augmenting 
from one to another is not easy to do, as multiple challenges arise. The most 
prevalent revolve around defining auditability while also safeguarding against 
attacks launched from the additional entity. Nevertheless, we single out three 
applications - namely data marketplaces, crowdsourcing systems, and financial 
auditing. For these applications, based on the identified limitations of prior 
works, we propose new systems that achieve auditability in the 3-entity 
setting. For the first, we propose an extension to the landscape of functional 
encryption, while for the rest we provide specific ideas on architectural 
design and component utilization.


Date:			Wednesday, 1 March 2023

Time:                  	2:00pm - 4:00pm

Venue:                  Room 4472
                         Lifts 25/26

Committee Members:	Dr. Dimitris Papadopoulos (Supervisor)
  			Prof. Cunsheng Ding (Chairperson)
 			Dr. Amir Goharshady
 			Prof. Ke Yi


**** ALL are Welcome ****