Bounded Collusion-Resistant Registered Functional Encryption for Circuits

Yijian Zhang; Jie Chen; Debiao He; Yuqing Zhang

Paper 2024/1572

Bounded Collusion-Resistant Registered Functional Encryption for Circuits

Yijian Zhang, Shanghai Key Laboratory of Trustworthy Computing, Software Engineering Institute, East China Normal University, Shanghai, China., Institute of Cybersecurity and Cryptology, School of Computing and Information Technology, University of Wollongong, Wollongong NSW, Australia.

Jie Chen, Shanghai Key Laboratory of Trustworthy Computing, School of Software Engineering, East China Normal University, Shanghai, China., Institute for Math & AI, Wuhan University, Wuhan, China.

Debiao He, School of Cyber Science and Engineering, Wuhan University, Wuhan, China.

Yuqing Zhang, National Computer Network Intrusion Protection Center, University of Chinese Academy of Sciences, China., School of Cyberspace Security, Hainan University, China.

Abstract

As an emerging primitive, Registered Functional Encryption (RFE) eliminates the key-escrow issue that threatens numerous works for functional encryption, by replacing the trusted authority with a transparent key curator and allowing each user to sample their decryption keys locally. In this work, we present a new black-box approach to construct RFE for all polynomial-sized circuits. It considers adaptive simulation-based security in the bounded collusion model (Gorbunov et al. - CRYPTO'12), where the security can be ensured only if there are no more than Q >= 1 corrupted users and is fixed at the setup phase. Unlike earlier works, we do not employ unpractical Indistinguishability Obfuscation (iO). Conversely, it can be extended to support unbounded users, which is previously only known from iO. Technically, our general compiler exploits garbled circuits and a novel variant of slotted Registered Broadcast Encryption (RBE), namely global slotted RBE. This primitive is similar to slotted RBE, but needs optimally compact public parameters and ciphertext, so as to satisfy the efficiency requirement of the resulting RFE. Then we present two concrete global slotted RBE from pairings and lattices, respectively. With proposed compiler, we hence obtain two bounded collusion-resistant RFE schemes. Here, the first scheme relies on k-Lin assumption, while the second one supports unbounded users under LWE and evasive LWE assumptions.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: A major revision of an IACR publication in ASIACRYPT 2024
Keywords: Functional Encryption Registered Encryption Bounded Collusion Model Simulation-Based Security
Contact author(s): yjzhangagra @ gmail com
s080001 @ e ntu edu sg
hedebiao @ whu edu cn
zhangyq @ ucas ac cn
History: 2025-02-13: last of 2 revisions; 2024-10-05: received; See all versions
Short URL: https://ia.cr/2024/1572
License: CC BY

BibTeX

@misc{cryptoeprint:2024/1572,
      author = {Yijian Zhang and Jie Chen and Debiao He and Yuqing Zhang},
      title = {Bounded Collusion-Resistant Registered Functional Encryption for Circuits},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/1572},
      year = {2024},
      url = {https://eprint.iacr.org/2024/1572}
}