Title: Amber - a New Family of Lattice-Based Threshold Encryption Schemes

Abstract: NIST recently launched a new call for Multi-Party Threshold Cryptography. In this talk, we will present Amber – a family of lattice-based threshold key encapsulation mechanisms (ThKEMs) that we plan to submit to NIST’s new call. The high-level design rationale of Amber is to lift a passively secure threshold identity-based encryption (ThIBE) using a one-time signature to an actively secure ThKEM. This is known as the BCHK-transform. The main effort is then to instantiate a practical ThIBE from lattices. We do so by leveraging new tools coming from rather recent developments in the field of lattice-based cryptography. We will also see how this template leads to different schemes, depending on your design choices. For instance, whether you care more about identifiable abort or security against adaptive corruptions. We conclude with interesting open problems in this area.

About the Speaker: Katharina Boudgoust is a CNRS researcher (Chargée de Recherche) and part of the ECO Team of the LIRMM research institute in Montpellier in France