Aggelos Kiayias - Biography#

Aggelos Kiayias is chair in Cyber Security and Privacy and director of the Blockchain Technology Laboratory at the University of Edinburgh. His work has made significant advances in blockchain technology and distributed systems, cryptography, e-voting and secure multiparty protocols as well as privacy and identity management. He holds a PhD in Computer Science from the City University of New York (2002) and a Mathematics degree from the National and Kapodistrian University of Athens, Greece (1996).

Selected Research Highlights

Two of his most influential contributions are in the analysis of blockchain protocols, where his work (jointly with Juan Garay and Nikos Leonardos) was first to define and prove the mathematical properties of the blockchain as a data structure (J. ACM 71(4): 25:1-25:49). He also was the lead designer of the Ouroboros proof of stake protocol (Crypto 2017 and Eurocrypt 2018) that demonstrated a similar security profile as the Bitcoin blockchain but operated at a small fraction of the energy cost solving in this way an important question in the blockchain space related to energy efficiency.

Kiayias has also contributed extensively to e-voting, collaborating with governments in the development of safe procedures for using e-voting machines as well as developing and testing prototypes of new e-voting systems. His work led to a number of safety improvements and attack mitigations that were deployed in election precincts in the state of Connecticut benefiting millions of voters. Kiayias and colleagues Michel, Russell, Schwarzmann also co-orchestrated what is now known as “risk limiting audits” at the state level. In these audits, suitably random sampled ballots from precincts across the state are collected and subsequently retallied using high precision industrial scanners in order to verify the reported tally calculations of the e-voting machines up to a suitable error level.

Of note also is Kiayias’ discovery (jointly with Argyros) of attacks and mitigations in widely used web software such as Mediawiki which is used by popular web-sites used by millions of people e.g., Wikipedia (cf. CVE-2012-1581). Following this work, Kiayias, jointly with Argyros and Stais in 2017, identified numerous vulnerabilities bypassing popular web application firewalls that are part of the standard arsenal of mechanisms for ensuring the robustness of the security perimeter of internal networks of homes and organizations.