Next Generation Laconic Cryptography

Communication efficiency is one of the central challenges for cryptography.

Modern distributed computing techniques work on large quantities of data, and critically depend on keeping the amount of information exchanged between parties as low as possible.

However, classical cryptographic protocols for secure distributed computation cause a prohibitive blow-up of communication in this setting.Laconic cryptography is an emerging paradigm in cryptography aiming to realize protocols for complex tasks with a minimal amount of interaction and a sub-linear overall communication complexity.

If we manage to construct truly efficient laconic protocols, we could add a cryptographic layer of protection to modern data-driven techniques in computing.

My initial results in laconic cryptography did not just demonstrate the potential of this paradigm, but proved to be a game-changer in solving several long standing open problems in cryptography, e.g. enabling me to construct identity-based encryption from weak assumptions.However, the field faces two major challenges: (a) Current constructions employ techniques that are inherently inefficient. (b) The most advanced notions in laconic cryptography are only known from very specific combinations of assumptions, and are therefore just one cryptanalytic breakthrough away from becoming void.This project will make a leap forward in both challenges.

I will systematically address these challenges in a work program which pursues the following objectives: (i) Develop new tools and mechanisms to realize crucial cryptographic primitives in a compact way. (ii) Design efficient protocols for advanced laconic functionalities which sidestep the need for inherently inefficient low-level techniques and widen the foundation of underlying assumptions. (iii) Strengthen the conceptual bridge between laconic cryptography and cryptographically secure obfuscation, transferring new techniques and ideas between these domains.