Panagiotis Chatzigiannis

Staff Research Scientist

Team: Digital currencies

Research areas: Security and privacy, blockchain, cryptocurrency

Dr. Panagiotis (Panos) Chatzigiannis joined Visa Research as a Staff Research Scientist in June 2022. Panos received his Ph.D. in Computer Science from George Mason University in August 2022 and his M.S. in Computer Science from Naval Postgraduate School in September 2012. During his Ph.D., his research focused on the field of cryptography and blockchains, primarily on blockchain auditability and auditable - accountable payment systems, blockchain on resource-constrained devices and improving usability of blockchain applications. He also worked on identifying attacks in practical implementations, such as broken proofs of liabilities in cryptocurrency exchanges and malleable base64 encodings in several programming languages. While at George Mason University, he worked as a summer intern and a part-time researcher with Facebook/Novi in Summer/Fall 2020 and Summer 2021.

As a member of the Blockchain team, his research interests are in blockchain, cryptocurrencies and cryptography, mainly implementing protocols that offer auditability functionalities in blockchain-based payment systems. He has published papers in several international conferences, including Privacy Enhancing Technologies Symposium (PETS), Financial Cryptography and Data Security (FC), European Symposium on Research in Computer Security (ESORICS), Applied Cryptography and Network Security (ACNS) and others.


  1. Foteini Baldimtsi, Panagiotis Chatzigiannis, S. Dov Gordon, Phi Hung Le, Daniel McVicker, "gOTzilla: Efficient Disjunctive Zero-Knowledge Proofs from MPC in the Head, with Application to Proofs of Assets in Cryptocurrencies", PETS 2022
  2. Panagiotis Chatzigiannis, Konstantinos Chalkias, "Base64 Malleability in Practice", AsiaCCS 2022
  3. Panagiotis Chatzigiannis, Foteini Baldimtsi, Konstantinos Chalkias, "SoK: Blockchain Light Clients", Financial Cryptography 2022
  4. Konstantinos Chalkias, Panagiotis Chatzigiannis, Yan Ji, "Broken Proofs of Solvency in Blockchain Custodial Wallets and Exchanges", Financial Cryptography Workshops 2022
  5. Panagiotis Chatzigiannis, Foteini Baldimtsi, Igor Griva, Jiasun Li, "Diversification across mining pools: Optimal mining strategies under PoW", Journal of Cybersecurity 2022
  6. Panagiotis Chatzigiannis, Konstantinos Chalkias, "Proof of Assets in the Diem Blockchain", ACNS Workshops 2021
  7. Panagiotis Chatzigiannis, Foteini Baldimtsi, Konstantinos Chalkias, "SoK: Auditability and Accountability in Distributed Payment Systems", ACNS 2021
  8. Panagiotis Chatzigiannis, Konstantinos Chalkias, Valeria Nikolaenko, "Homomorphic Decryption in Blockchains via Compressed Discrete-Log Lookup Tables", DPM/CBT@ESORICS 2021
  9. Panagiotis Chatzigiannis, Foteini Baldimtsi, "MiniLedger: Compact-Sized Anonymous and Auditable Distributed Payments", ESORICS 2021
  10. Sam Blackshear, Konstantinos Chalkias, Panagiotis Chatzigiannis, Riyaz Faizullabhoy, Irakliy Khaburzaniya, Eleftherios Kokoris-Kogias, Joshua Lind, David Wong, Tim Zakian, "Reactive Key-Loss Protection in Blockchains", Financial Cryptography Workshops 2021
  11. Panagiotis Chatzigiannis, Foteini Baldimtsi, Constantinos Kolias, Angelos Stavrou, "Black-Box IoT: Authentication and Distributed Storage of IoT Data from Constrained Sensors", IoTDI 2021