Recent Publications

Önder Askin, Holger Dette, Martin Dunsche, Tim Manfred Kutta, Yun Lu, Yu Wei, and Vassilis Zikas
General-Purpose f-DP Estimation and Auditing in a Black-Box Setting
Usenix Security 2025 (to appear)
A preliminary full version is available here: [PDF]

Privacy and AI

Lucas Piske, Vladimir Kolesnikov, Jaspal Singh, Ni Trieu, and Vassilis Zikas
Distance-Aware OT with Application to Fuzzy PSI
ACM Conference on Computer and Communications Security — CCS 2025 (to appear)
A preliminary full version is available here: [PDF]

Cryptography   MPC

Michele Ciampi, Yun Lu, Rafail Ostrovsky, and Vassilis Zikas
Two-tier Black-box Blockchains and Application to Instant Layer-1 Payments
ACM Conference on Advances in Financial Technologies — AFT 2025, ACM, pp 19:1–19:24, 2025.
A preliminary full version is available here: [PDF]

Blockchain & Cryptocurrencies  Cryptography

Wonseok Choi, Xiangyu Liu, and Vassilis Zikas
Blockchain Governance via Sharp Anonymous Multisignatures
ACM Conference on Advances in Financial Technologies — AFT 2025, ACM, pp 5:1–5:24, 2025.
A preliminary full version is available here: [PDF]

Blockchain & Cryptocurrencies  Cryptography

Michele Ciampi, Xiangyu Liu, Ioannis Tzannetos, and Vassilis Zikas
Universal Adaptor Signatures from Blackbox Multi-party Computation
{RSA} Conference, Cryptographers' Track — CT-RSA 2025 (to appear). 
A preliminary full version is available here: [ PDF]

Cryptography  MPC  Blockchain & Cryptocurrencies

Nishanth Chandran, Juan Garay, Ankit Misra, Rafail Ostrovsky, and Vassilis Zikas
Adaptive Security, Erasures, and Network Assumptions in Communication-Local MPC
Theory of Cryptography Conference — TCC 2024 (to appear). 
A preliminary full version is available here: [ PDF ]

MPC

Jaspal Singh, Yu Wei, and Vassilis Zikas
Information-Theoretic Multi-Server Private Information Retrieval with Client Preprocessing
Theory of Cryptography Conference — TCC 2024 (to appear). 
A preliminary full version is available here: [ PDF ]

Cryptography   MPC

Konstantinos Brazitikos and Vassilis Zikas
General Adversary Structures in Byzantine Agreement and Multi-Party Computation with Active and Omission Corruption
Theory of Cryptography Conference — TCC 2024 (to appear). 
A preliminary full version is available here: [ PDF ]

MPC   Distributed Computing

Xiangyu Liu, Ioannis Tzannetos, and Vassilis Zikas
Adaptor Signatures: New Security Definition and A Generic Construction for NP Relations
Advances in Cryptology — ASIACRYPT 2024 (to appear).
A preliminary full version is available here: [ PDF ]

Blockchain & Cryptocurrencies   Cryptography

Timothé Albouy, Davide Frey, Ran Gelles, Carmit Hazay, Michel Raynal, Elad Michael Schiller, François Taïani, and Vassilis Zikas 
Near-Optimal Communication Byzantine Reliable Broadcast under a Message Adversary
Conference on Principles of Distributed Systems — OPODIS 2024 (to appear).
A preliminary full version is available here: [ PDF ]

Distributed Computing

Yun Lu, Malik Magdon-Ismail, Yu Wei, and Vassilis Zikas
Eureka: A General Framework for Black-box Differential Privacy Estimators
IEEE Symposium on Security and Privacy — S&P 2024, IEEE, pp 913–931, 2024.
A preliminary full version is available here: [ PDF ]

Privacy and AI

Christian Badertscher, Peter Gazi, Aggelos Kiayias, Alexander Russell, and Vassilis Zikas:
Consensus Redux: Distributed Ledgers in the Face of Adversarial Supremacy 
IEEE Computer Security Foundations Symposium —CSF 2024, IEEE, pp 143–158, 2024.
A preliminary full version is available here: [ PDF ]

Blockchain and Cryptocurrencies

Ran Cohen, Pouyan Forghani, Juan Garay, Rutvik Patel, and Vassilis Zikas
Concurrent Asynchronous Byzantine Agreement in Expected-Constant Rounds, Revisited
Theory of Cryptography Conference — TCC 2023, LNCS, Springer, vol 14372, pp 422–451, 2023.
A preliminary full version is available here: [ PDF ]

Cryptography  Distributed Computing

Lindsey Kennard, Muhammad Ishaq, Benjamin Levy, Ana Milanova, Ben Sherman, and Vassilis Zikas. 
COMBINE: COMpilation and Backend-INdependent vEctorization for Multi-Party Computation
ACM Conference on Computer and Communications Security — CCS 2023, ACM, pp 2531–2545, 2023.
A preliminary full version is available here: [ PDF ]

MPC

Ran Cohen, Juan Garay, and Vassilis Zikas. 
Completeness Theorems for Adaptively Secure Broadcast
Advances in Cryptology — CRYPTO 2023, LNCS, Springer, vol 14081, pp 3–38, 2023
A preliminary full version is available here: [ PDF ]

Cryptography  Distributed Computing

Michele Ciampi, Rafail Ostrovsky, Hendrik Waldner, and Vassilis Zikas
Round-Optimal and Communication-Efficient Multiparty Computation
Advances in Cryptology — EUROCRYPT 2022, LNCS, Springer, vol 13275, pp 65–95, 2022.
A preliminary full version is available here: [ PDF ]

MPC

Michele Ciampi, Yun Lu, and Vassilis Zikas
Collusion-Preserving Computation without a Mediator
IEEE Computer Security Foundations Symposium —CSF 2022, IEEE, pp 211–226, 2022.
A preliminary full version is available here: [ PDF ]

MPC  Game Theory  Blockchain and Cryptocurrencies

John Andrews, Michele Ciampi, and Vassilis Zikas
Etherless Ethereum Tokens: Simulating Native Tokens in Ethereum
Symposium on Cyber Security, Cryptology and Machine Learning —CSCML 2022, LNCS, Springer, vol 13301, pp 388–407, 2022.
(Best Paper Award)
A preliminary full version is available here: [ PDF ]

Blockchain and Cryptocurrencies

Michele Ciampi, Muhammad Ishaq, Malik Magdon-Ismail, Rafail Ostrovsky and Vassilis Zikas
FairMM: A Fast and Frontrunning-Resistant Crypto Market-Maker
Symposium on Cyber Security, Cryptology and Machine Learning —CSCML 2022, LNCS, Springer, vol 13301, pp 428–466, 2022.
A preliminary full version is available here: [ PDF ]

Blockchain and Cryptocurrencies

Nishanth Chandran, Pouyan Forghani, Juan A. Garay, Rafail Ostrovsky, Rutvik Patel, and Vassilis Zikas
Universally Composable Almost-Everywhere Secure Computation.
Conference on Information-Theoretic Cryptography —ITC 2022, LIPIcs, vol 230, pp 14:1–14:25, 2022.
A preliminary full version is available here: [ PDF ]

MPC

Christian Badertscher, Yun Lu, and Vassilis Zikas
A Rational Protocol Treatment of 51% Attacks
Advances in Cryptology — CRYPTO 2021, LNCS, Springer, vol 12827, pp 3–32, 2021.
A preliminary full version is available here: [ PDF ]

Blockchain and Cryptocurrencies  Game Theory

Christian Badertscher, Peter Gazi, Aggelos Kiayias, Alexander Russell, and Vassilis Zikas
Dynamic Ad Hoc Clock Synchronization via Proof of Stake
Advances in Cryptology — EUROCRYPT 2021, LNCS, Springer, vol 12698, pp 399–428, 2021.
A preliminary full version is available here: [ PDF ]

Blockchain and Cryptocurrencies

Christian Badertscher, Julia Hesse, and Vassilis Zikas
On the (Ir)Replaceability of Global Setups, or How (Not) to Use a Global Ledger
Theory of Cryptography Conference — TCC 2021, LNCS, Springer, vol 13043, pp 626–657, 2021.
A preliminary full version is available here: [ PDF ]

Cryptography   Blockchain and Cryptocurrencies

Christian Badertscher, Ran Canetti, Julia Hesse, Björn Tackmann, and Vassilis Zikas
Universal Composition with Global Subroutines: Capturing Global Setup within Plain UC
Theory of Cryptography Conference — TCC 2020, LNCS, Springer, vol 12552, pp 1–30, 2020.
A preliminary full version is available here: [ PDF ]

Cryptography

Ao Liu, Yun Lu, Lirong Xia, and Vassilis Zikas
How Private Is Your Voting? A Framework for Comparing the Privacy of Voting Mechanisms
Uncertainty in Artificial Intelligence — UAI 2020, AUAI Press, PMLR vol 124, 2020. Preliminary version appeared at WADE 2018.
A preliminary full version is available here: [ PDF ]

Privacy & AI

Ran Cohen, Juan Garay, and Vassilis Zikas
Broadcast-Optimal Two-Round MPC
Advances in Cryptology — EUROCRYPT 2020, LNCS, Springer, vol 12106, pp 428–858, 2020.
A preliminary full version is available here: [ PDF ]

MPC

Juan Garay, Aggelos Kiayias, Rafail Ostrovsky, Giorgos Panagiotakos, and Vassilis Zikas
Resource-Restricted Cryptography: Revisiting MPC Bounds in the Proof-of-Work Era
Advances in Cryptology — EUROCRYPT 2020, LNCS, Springer, vol 12106, pp 129–158, 2020.
A preliminary full version is available here: [ PDF ]

Blockchain and Cryptocurrencies

Michele Ciampi, Aydin Kheirbakhsh Abadi, Aggelos Kiayias, and Vassilis Zikas
Timed Signatures and Zero-Knowledge Proofs: Timestamping in the Blockchain Era
Applied Cryptography and Network Security — ACNS 2020, LNCS, Springer, vol 12146, pp 335–354, 2020.
A preliminary full version is available here: [ PDF ]

Blockchain and Cryptocurrencies  Cryptography

Leonard Kleinrock, Rafail Ostrovsky, and Vassilis Zikas
Proof-of-Reputation Blockchain with Nakamoto Fallback
INDOCRYPT 2020 (to appear).
A preliminary full version is available here: [ PDF ]

Blockchain and Cryptocurrencies

Muhammad Ishaq, Ana Milanova, and Vassilis Zikas
Efficient MPC via Program Analysis: A Framework for Efficient Optimal Mixing
ACM Conference on Computer and Communications Security — CCS 2019, ACM, pp 1539–1556, 2019.
A preliminary full version is available here: [ PDF ]

MPC

Thomas Kerber, Markulf Kohlweiss, Aggelos Kiayias, and Vassilis Zikas
Ouroboros Crypsinous: Privacy-Preserving Proof-of-Stake
IEEE Symposium on Security and Privacy — S&P 2019, IEEE, pp 157–174, 2019.
A preliminary full version is available here: [ PDF ]

Blockchain and Cryptocurrencies