Dynamic Decentralized Functional Encryption

Jérémy Chotard; Edouard Dufour-Sans; Romain Gay; Duong Hieu Phan; David Pointcheval

Paper 2020/197 Original: eprint.iacr.org/2020/197 ↗

Dynamic Decentralized Functional Encryption

Jérémy Chotard

Edouard Dufour-Sans

Romain Gay

Duong Hieu Phan

David Pointcheval

Abstract

We introduce Dynamic Decentralized Functional Encryption (DDFE), a generalization of Functional Encryption which allows multiple users to join the system dynamically, without relying on a trusted third party or on expensive and interactive Multi-Party Computation protocols. This notion subsumes existing multi-user extensions of Functional Encryption, such as Multi-Input, Multi-Client, and Ad Hoc Multi-Input Functional Encryption. We define and construct schemes for various functionalities which serve as building-blocks for latter primitives and may be useful in their own right, such as a scheme for dynamically computing sums in any Abelian group. These constructions build upon simple primitives in a modular way, and have instantiations from well-studied assumptions, such as DDH or LWE. Our constructions culminate in an Inner-Product scheme for computing weighted sums on aggregated encrypted data, from standard assumptions in prime-order groups in the Random Oracle Model.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint.
History: 2020-09-06: last updated; 2020-02-18: published
Short URL: https://ia.cr/2020/197
License: https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2020/197,
      author = {Jérémy Chotard and Edouard Dufour-Sans and Romain Gay and Duong Hieu Phan and David Pointcheval},
      title = {Dynamic Decentralized Functional Encryption},
      howpublished = {Cryptology {ePrint} Archive, Paper 2020/197},
      year = {2020},
      url = {https://eprint.iacr.org/2020/197}
}