Welcome back, Antoine

We’re thrilled to welcome Antoine Urban back to Dfns as Senior Cryptographer, just after successfully defending his PhD on secure delegated multiparty computation at Institut Polytechnique de Paris. Antoine first joined Dfns in 2023 as a research intern, where he co-designed and implemented our now widely recognized Rust-based threshold ECDSA protocol, KU23, in collaboration with Dr. Jonathan Katz. He now returns full-time to deepen our cryptographic research and help build the next generation of wallet security.

A life in MPC, FHE, and delegated computation

Antoine is a specialist in secure multiparty computation (MPC), cryptographic protocols in general, and privacy-preserving systems. He recently defended his PhD at Institut Polytechnique de Paris, where his work focused on efficient delegated secure MPC using homomorphic encryption. In his thesis, he explored how a group of data owners can securely delegate computations to untrusted cloud servers using fully homomorphic encryption (FHE), while ensuring correctness, privacy, and minimal interaction. His contributions include a robust FHE-based MPC protocol and a generic framework for low-round communication, paving the way for scalable, privacy-preserving computation in real-world deployments. It’s a vision that strongly resonates with our approach to secure key management.

Antoine’s research sits at the crossroads of cryptographic theory and applied security. His doctoral work introduced a scalable, robust framework for delegated secure multiparty computation using homomorphic encryption, allowing untrusted cloud servers to perform secure computation on behalf of data owners with strong guarantees around correctness, privacy, and efficiency. 

These ideas closely align with our vision at Dfns: to build infrastructure that is both cryptographically secure and practically usable by developers and institutions alike. Prior to his academic work, Antoine held roles at SAP, PayPal, and the NUS Fintech Society, where he gained hands-on experience in privacy frameworks, applied security, and blockchain education.

Advancing MPC, post-quantum security, and wallet safety

Antoine will lead and contribute to several major initiatives at Dfns Labs, our applied research unit operating under the umbrella of the Linux Foundation and LF Decentralized Trust, as well as in collaboration with the MPC Alliance:

• Post-Quantum Threshold Signatures (PQ-TSS): Antoine is spearheading a state-of-the-art analysis of PQ-TSS schemes and will lead the design of a new post-quantum secure threshold signature protocol, anticipating future cryptographic standards beyond ECDSA and EdDSA.
• FIPS 140-3 Certified MPC Module: He will also oversee the development and submission of one of the world's first FIPS 140-3 certified MPC libraries (only the third after Unbound and Sepior). This work aims to broaden MPC acceptance among global financial institutions and regulations.
• MPC in HSMs (with IBM and Thales): As banks increasingly demand hardware-rooted security, Antoine is collaborating with research teams at IBM and Thales to bring MPC protocols into HSM environments, making MPC compatible with existing compliance and hardware ecosystems.
• Standardizing KU23 and Advancing KU25: KU23, our original threshold ECDSA protocol, is being proposed for standardization at the NIST level, with Antoine driving this process. In parallel, he’s developing KU25, our next iteration that matches properties from DKLS24 to support even stronger robustness, auditability, and forward secrecy guarantees.
• Data Integrity Framework: Internally, Antoine will contribute to the design of a new data integrity framework that ensures the end-to-end correctness of signing operations, from intent capture to valid signature generation, while protecting against malicious code injection or internal threats that could compromise transaction trust.

Building the future of wallet security

Antoine’s return marks an important step forward as we expand Dfns Labs’ research and engineering capabilities. With more regulated institutions entering crypto and digital asset custody, the demand for auditable, standards-compliant security infrastructure is growing rapidly. Antoine's contributions will help shape the cryptographic foundations of this new era. We're proud to have him back.

We're growing our team of engineers, cryptographers, and product builders.

• Explore open roles: welcometothejungle.com/en/companies/dfns/jobs
• Learn more about Dfns: dfns.co 
• And Dfns Labs: dfns.co/labs