Stefanos Chaliasos

Assistant Professor, UCL
Senior Security Researcher, zkSecurity

Stefanos Chaliasos is a Senior Security Researcher at ZKSecurity and an Assistant Professor at UCL. His work sits at the intersection of Zero-Knowledge Proofs (ZKPs), blockchain, security, AI, payments, privacy, and digital trust.

He completed his PhD at Imperial College London working in the areas of Zero-Knowledge Proofs, Blockchain, Security, and Mechanism Design under the supervision of Dr Ben Livshits and Professor Alastair F. Donaldson. He has also worked in industry since 2018 across roles spanning software engineering, applied cryptography, security research, and industrial research.

His main research interests involve Blockchain Security, Software Testing, ZKPs, Mechanism Design, Program Analysis, LLMs for Security, LLMs for Payments and Programming Languages.

On top of that, he has built LLM-enhanced security pipelines that have detected vulnerabilities in cryptographic libraries from Cloudflare, Bron, and other state-of-the-art cryptographic libraries, and he is also an active white-hat hacker, having discovered zero-day vulnerabilities in live systems securing billions of USD and received bug bounties from Tools for Humanity, Optimism, Linea, zkSync Era, and OpenVM.

Alongside research and teaching, he works with banks, fintechs, payments companies, and leadership teams that want technically credible, business-facing guidance on how these technologies translate into real institutional decisions, product strategy, and infrastructure choices.

Recent Talks

  • International Executive MBA @UCL (2026): Stablecoins and Privacy for Institutional Adoption of Blockchain

  • TLDR Conference (2025): Data-Oriented Denial-of-Service Attacks on ZK-Rollup TFMs

  • ZKProof 7 (2025): Towards a Formal Foundation for Blockchain ZK Rollups

  • Devcon (2024): What don’t we know? Understanding Security Vulnerabilities in SNARKs

  • Ethereum Engineering Group Meetup (Nov’24): SoK: What don’t we know? Understanding Security Vulnerabilities in SNARKs

Selected Publications

  1. ASPLOS’26
    Evaluating Compiler Optimization Impacts on zkVM Performance
    Thomas Gassmann, Stefanos Chaliasos, Thodoris Sotiropoulos, and Zhendong Su
    2026
    PDF
  2. SP’26
    Language-Agnostic Detection of Computation-Constraint Inconsistencies in ZKP Programs via Value Inference
    Arman Kolozyan, Bram Vandenbogaerde, Janwillem Swalens, Lode Hoste, Stefanos Chaliasos, and Coen De Roover
    2026
    PDF
  3. PrePrint’25
    Unaligned Incentives: Pricing Attacks Against Blockchain Rollups
    Stefanos Chaliasos, Conner Swann, Sina Pilehchiha, Nicolas Mohnblatt, Benjamin Livshits, and Assimakis Kattis
    2025
    PDF
  4. CCS’25
    Towards a Formal Foundation for Blockchain Rollups
    Stefanos Chaliasos, Denis Firsov, and Benjamin Livshits
    2025
    PDF
  5. USENIX SEC’24
    SoK: What don’t we know? Understanding Security Vulnerabilities in SNARKs
    Stefanos Chaliasos, Jens Ernstberger, David Theodore, David Wong, Mohammad Jahanara, and Benjamin Livshits
    2024
    PDF Dataset
  6. ICSE’24
    Smart Contract and DeFi Security: Insights from Tool Evaluations and Practitioner Surveys
    Stefanos Chaliasos, Marcos Antonios Charalambous, Liyi Zhou, Rafaila Galanopoulou, Arthur Gervais, Dimitris Mitropoulos, and Ben Livshits
    2024
    PDF Code Artifact
  7. USENIX SEC’23
    The blockchain imitation game
    Kaihua Qin, Stefanos Chaliasos, Liyi Zhou, Benjamin Livshits, Dawn Song, and Arthur Gervais
    2023
    PDF
  8. PLDI’22
    Finding Typing Compiler Bugs
    Stefanos Chaliasos*, Thodoris Sotiropoulos*, Diomidis Spinellis, Arthur Gervais, Ben Livshits, and Dimitris Mitropoulos
    In Proceedings of the 43nd ACM SIGPLAN International Conference on Programming Language Design and Implementation 2022
    * Both authors contributed equal
    Distinguished Paper Award and Best Artifact Award 🏆🏆
    PDF Code Artifact Website DOI