International Association for Cryptologic Research

International Association
for Cryptologic Research


Dynamic Decentralized Functional Encryption

Jérémy Chotard , ENS, University of Limoges
Edouard Dufour-Sans , Carnegie Mellon University
Romain Gay , Cornell Tech
Duong Hieu Phan , ENS, University of Limoges
David Pointcheval , ENS, CNRS, Inria, PSL University
DOI: 10.1007/978-3-030-56784-2_25 (login may be required)
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Presentation: Slides
Conference: CRYPTO 2020
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.
Video from CRYPTO 2020
  title={Dynamic Decentralized Functional Encryption},
  author={Jérémy Chotard and Edouard Dufour-Sans and Romain Gay and Duong Hieu Phan and David Pointcheval},