Multiparty Homomorphic Encryption: From Theory to Practice

Multiparty homomorphic encryption (MHE) techniques enable secure multiparty computation (MPC) with low requirements for the input parties. Notably, these protocols have low communication complexity, most of their execution cost can be outsourced, and they can tolerate churn. But, despite being promising in theory, MHE-based MPC solutions have not yet been implemented in any of the 30+ existing MPC frameworks, thus revealing a gap between theory and practice. This presentation summarizes my prior and current work toward closing this gap by proposing contributions to both sides.
On the theoretical side, I will present two MHE constructions that extend the new generation of HE schemes to the multiparty setting. On the practical side, I will present the Lattigo library and the Helium system. Lattigo is an open-source Go package that implements the state-of-the-art HE schemes, along with their multiparty extensions. Helium builds on Lattigo and will provide the first open-source end-to-end implementation of an MHE-based MPC protocol.


Bio
Christian Mouchet recently obtained his PhD from EPFL, where he was advised by Prof. Carmela Troncoso and Prof. Jean-Pierre Hubaux. His research focuses on applied cryptography, particularly for secure multiparty computation protocols and their implementation. He is the founder and a maintainer of Lattigo, an open-source library for multiparty homomorphic encryption.