Laconic Cryptography: New paradigms, constructions and directions

Abstract. 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. Abstractly, laconic cryptography can be thought of as a reverse delegation paradigm, where the party that does the computation is also the one that obtains the result. This approach enabled several new results such as identity-based encryption from new assumptions (CDH), rate-1 oblivious transfer, laconic function evaluation, and much more. In addition, techniques from laconic cryptography have been useful to build registration-based encryption (RBE), a new proposal to solve the key escrow problem in identity-based encryption. In this talk I will survey the origins of this field, how it provided new angles of attack on some of the major open problems in public key cryptography, and what challenges remain to unlock the full potential of this paradigm.

Suggested readings: ia.cr/2023/404, ia.cr/2022/1505, https://laconiccryptography.github.io/2024

[Slides]