Antonio Sanso is a Spanish cryptographer, security researcher, and software engineer who is a researcher at the Ethereum Foundation. ^{[1] [2]} He is a prominent figure in the fields of post-quantum cryptography (PQC) and zero-knowledge proofs (ZKPs), contributing significantly to academic research, open-source development, and the long-term security strategy of the Ethereum protocol. ^{[3] [4]}​

Education

Antonio Sanso completed his doctoral studies in Spain, earning a Ph.D. in Computer Science from the Universidad de Vigo between 2007 and 2010. His doctoral thesis was titled "A framework for the massive evaluation of web accessibility." He also received a Master of Science in Computer Science from the same institution between 2002 and 2007. ^[1]

His academic background is extensive and also includes postgraduate work in fields directly related to his later specialization in cryptography. Various professional profiles indicate studies in Computer Security at EURECOM in France; a Master of Science in Network and Information Technologies from Universitat Pompeu Fabra; and both a Bachelor's and Master's degree in Telecommunication Engineering from the Università degli Studi di Napoli Federico II in Italy. This diverse educational history reflects a transition from general computer science and web technologies to a deep specialization in privacy-enhancing technologies and applied cryptography. ^{[5] [4]}

Career

Sanso's career shows a clear progression from software engineering and big data into specialized security research roles at major technology corporations, before moving into the blockchain industry and ultimately joining the Ethereum Foundation. ^[4]​

Early Career and Transition to Blockchain

Sanso's early professional experience was in software development, including a role as a Software Engineer at Igalia from 2005 to 2007. Following his Ph.D., he worked as a Postdoctoral Researcher at the IMDEA Software Institute from 2011 to 2013. His career then moved into the enterprise sector, where he worked as a Senior Consultant for Deloitte Switzerland until the end of 2015 and as a Senior Big Data Engineer for Swisscom until late 2018. During this period, his focus was on big data infrastructure and technology consulting. ^[1]​

Other sources indicate parallel or subsequent experience in security research roles at several major technology and telecommunications firms. These positions include a research role at Nokia, a position as a Senior Security Researcher at Telefónica I+D, and a role as Lead Security Researcher at Ericsson. He is also noted as having been a software engineer at CERN, the European Organization for Nuclear Research. This period marks his professional shift towards a focus on information security and cryptography. ^{[3] [4]}​

Web3 and Blockchain Security

Sanso transitioned into the blockchain industry, taking on a series of specialized roles at prominent crypto-native organizations. He worked as a Security Researcher for the Bitfury Group, a major Bitcoin mining and blockchain technology company, and as a Security Engineer at ConsenSys, where he was part of the ConsenSys Diligence security auditing team. ^{[4] [5]}​

His expertise in ZKPs led to positions focused on Layer 2 scaling solutions. He was a Senior Protocol Engineer at Matter Labs, the company developing zkSync, and served as a Senior Cryptography Engineer at Edge & Node, the initial team behind The Graph. While at Nethermind from November 2021 to June 2023, he worked as a Security Engineer focusing on ZKPs, particularly the Starknet ecosystem and its native language, Cairo. He also had roles as Head of Blockchain Engineering at Blacture and as a Security Researcher at NEXO. ^{[5] [1] [3]}​

From May to September 2021, Sanso was a Security Engineer at the Celo Foundation. There, he was a key contributor to the "Plumo" project, which utilizes zk-SNARKs to create an ultra-lightweight client for the Celo blockchain, enabling mobile devices to sync with the network efficiently and trustlessly. ^[3]​

Ethereum Foundation

Sanso joined the Ethereum Foundation as a Security Researcher around September 2021 and is a member of the Protocol Support Team. ^{[3] [5]} His work involves researching and reinforcing the cryptographic primitives that underpin the Ethereum protocol, contributing to its overall robustness and long-term security. He is also a member of the Protocol Guild, a collective of core Ethereum contributors. ^[6]​

His most prominent role at the foundation is as a leading member of the post-quantum security team. This initiative, formally established in late 2023, is tasked with preparing the Ethereum protocol for the eventual threat posed by quantum computers. ^[4]​

Major Works and Contributions

Post-Quantum Cryptography at Ethereum

In late 2023, the Ethereum Foundation announced the formation of a dedicated post-quantum (PQ) security team, informally known as "PQ Grill," to make Ethereum's core protocol resistant to attacks from future quantum computers. ^[1] Antonio Sanso co-leads this initiative alongside fellow researcher Dankrad Feist. ^[1] The team's mission is to research, test, and shepherd the necessary upgrades, including exploring and implementing quantum-resistant signature schemes. ^[4]​

As part of this effort, Sanso has been instrumental in organizing the community around the "Post-Quantum Transaction Signature (PQTS)" initiative. This project aims to transition Ethereum's account signatures to a quantum-resistant standard, exploring changes to Externally Owned Accounts (EOAs) and leveraging account abstraction. His work includes organizing developer workshops and working groups; for instance, he was responsible for organizing a kickoff call for the PQTS working group scheduled for February 4, 2026. ^[6]​

In a social media post on January 24, 2026, Sanso explained the necessity of this work in plain terms (translated from Italian):

"Ok, let's talk about post-quantum without the fluff. PQ means preparing for the day when quantum computers make some of the primitives we take for granted today vulnerable, especially signatures like ECDSA and EdDSA. It's not 'tomorrow morning,' but it's the classic high-impact, low-probability risk that you can't ignore." ^[2]

Zero-Knowledge Proofs (ZKPs)

Sanso is widely recognized for his work in the field of ZKPs, contributing to both their theoretical understanding and practical application. He is well-regarded for his ability to explain complex cryptographic concepts through his writing and conference talks. ^[1]​

His contributions include:

• Systematization of Knowledge (SoK) Papers: He has co-authored multiple influential SoK papers that serve as foundational educational resources for the ZKP field. These include SoK: A taxonomy of ZK-SNARKs for the curious (2021) and SoK: The great ditch of the ZK-SNARKs (2023). ^[3]
• Cryptanalysis: His research includes analyzing the security of cryptographic primitives used in ZK systems. One recent e-print merges two research papers to introduce the use of a "Graeffe transform" to accelerate interpolation attacks on the Poseidon hash function, which is widely used in ZK circuits. ^[2]
• Open-Source Tools: He contributes to core Ethereum repositories related to ZKP security. Notably, he has contributed fixes to ethereum/soundcalc, a tool used to calculate the soundness of cryptographic proofs, including those based on advanced primitives like DEEP-ALI and LogUp. This work is critical for ensuring the security of ZK-Rollups. ^[6]
• Project Implementation: His work at Celo on the Plumo light client and at Nethermind with Starknet and Cairo demonstrates his experience in applying ZKPs in production environments. He also created zk-schnorr-python, a Python implementation of a ZK Schnorr proof system. ^{[3] [1]}

Web Security and Identity

Prior to his deep focus on the blockchain space, Sanso established himself as an expert on web security and authorization protocols. He is the co-author of the book OAuth 2.0 in Action, published by Manning. The book is considered a definitive guide to the OAuth 2.0 framework, a critical standard for authorization and identity management on the modern web. He helps maintain the official source code for the book's examples in a public GitHub repository. ^[6]​

Academic Research and Publications

Sanso maintains an active academic profile with over 1,500 citations for his work as of early 2026. ^[4] His research interests have evolved from web accessibility to a primary focus on applied cryptography, privacy-preserving systems, and blockchain security. ^[1]​

In addition to his SoK papers and the book on OAuth, his notable publications include:

• "Coconut: Threshold Issuance for Unlinkable and Anonymous Credentials": A significant paper on a privacy-preserving credential system that enables distributed trust and user anonymity.
• "ZEXE: Enabling Decentralized Private Computation": Research co-authored on a system for executing private computations off-chain with on-chain verification, a foundational concept for many ZK-based Layer 2 solutions.
• "Plumo: A light-weight zk-SNARK verifier for Celo" (2022): The academic paper detailing the lightweight client protocol he helped develop.
• "A survey of security and privacy in the metaverse" (2022): Research exploring security challenges in emerging virtual worlds.
• "SCS: A stateless client-side encryption scheme for untrusted clouds" (2016): Work focused on cloud security and user data protection.

These publications demonstrate his long-standing contributions to the fields of privacy, decentralized systems, and applied cryptography. ^{[5] [3] [4]}​