home • publications & preprints • phd 

About me

Tancrède Lepoint works as Applied Scientist in the AWS Privacy Engineering team. He is a cryptographer, specialized in privacy-enhancing technologies, lattice-based cryptography, post-quantum cryptography, homomorphic encryption, and differential privacy.

He is a director of the International Association for Cryptologic Research (2018-2023) and co-editor of the Cryptology ePrint Archive since 2016. He worked at Apple (2021-2022), Google (2018-2021), SRI International (2016-2018), and CryptoExperts (2011-2016). He holds a Ph.D. in Computer Science from École Normale Supérieure and University of Luxembourg.

Tancrède co-authored the two post-quantum cryptographic primitives (CRYSTALS-Kyber and CRYSTALS-Dilithium) selected for standardization by NIST. He drove the cryptographic deployment of the Exposure Notifications Privacy-preserving Analytics within Google, a differentially-private multiparty computation system based on the private measurement system Prio. He also designed the multi-server verification flow for Exposure Notifications in the US. He worked on lightweigth anonymous credentials (Privacy-Pass, trust tokens) and specializes in homomorphic encryption.

Other news

• September 2022: The first beta version of fhe.rs, a Fully Homomorphic Encryption library written in pure Rust, is now available! It currently contains an RNS-variant of the BFV homomorphic encryption scheme, and features great performances and an easy-to-use API. In other exciting news, I started as applied scientist in the AWS Privacy Engineering team.
• July 2022: CRYSTALS-Kyber and CRYSTALS-Dilithium were selected for standardization by NIST! In other news, I left Apple to focus on a more research-oriented carreer.
• Apr 2022: The chapter Private Set Intersection and Compute of the Protecting Privacy through Homomorphic Encryption book is now available. The preprint Communication-efficient proactive MPC for dynamic groups with dishonest majorities has been accepted for publication at ACNS 2022. The preprint In-app cryptographically-enforced selective access control for Microsoft office and similar platforms has been accepted for publication at CSCML 2022.
• Aug. 2021: Our preprint Private Join and Compute from PIR with Default has been accepted for publication at Asiacrypt 2021, and On the (in)security of ROS has received the best paper award at Eurocrypt 2021.
• Jun. 2021: Our preprint Advances and Open Problems in Federated Learning is now published in Foundations and Trends in Machine Learning, Volume 14.

Program committees

• 2023: USENIX SECURITY, CRYPTO, PKC, CT-RSA.
• 2022: USENIX SECURITY.
• 2021: CHES, USENIX SECURITY, IEEE S&P, CT-RSA.
• 2020: WAHC (chair), CHES, USENIX SECURITY, EUROCRYPT, CT-RSA.
• 2019: SSR, WAHC (chair), USENIX SECURITY, PKC, CT-RSA.
• 2018: SSR, WAHC, SCN, CHES, CRYPTO, AFRICACRYPT, COSADE, PQCRYPTO, CT-RSA.
• 2017: INDOCRYPT, CANS, CHES, PQCRYPTO, EUROCRYPT, WAHC, CT-RSA.
• 2016: CHES, ICITS, WAHC.
• 2015: CANS, SECICT, ACNS, ACISP, WAHC.