Paper 2021/524

Decentralized Multi-Client Functional Encryption for Set Intersection with Improved Efficiency

Kwangsu Lee, Sejong University
Abstract

Functional encryption (FE) is a new paradigm of public key encryption that can control the exposed information of plaintexts by supporting computation on encrypted data. In this paper, we propose efficient multi-client FE (MCFE) schemes that compute the set intersection of ciphertexts generated by two clients. First, we propose an MCFE scheme that calculates the set intersection cardinality (MCFE-SIC) and prove its static security under dynamic assumptions. Next, we extend our MCFE-SIC scheme to an MCFE scheme for set intersection (MCFE-SI) and prove its static security under dynamic assumptions. The decryption algorithm of our MCFE-SI scheme is more efficient than the existing MCFE-SI scheme because it requires fewer pairing operations to calculate the intersection of two clients. Finally, we propose a decentralized MCFE scheme for set intersection (DMCFE-SI) that decentralizes the generation of function keys. Our MCFE schemes can be effectively applied to a privacy-preserving contact tracing system to prevent the spread of recent infectious diseases.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Published elsewhere. Minor revision. Designs, Codes and Cryptography
DOI
10.1007/s10623-022-01139-8
Keywords
Functional encryptionMulti-client settingPrivate set intersectionContact tracingBilinear maps.
Contact author(s)
kwangsu @ sejong ac kr
History
2024-02-13: last of 2 revisions
2021-04-23: received
See all versions
Short URL
https://ia.cr/2021/524
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2021/524,
      author = {Kwangsu Lee},
      title = {Decentralized Multi-Client Functional Encryption for Set Intersection with Improved Efficiency},
      howpublished = {Cryptology ePrint Archive, Paper 2021/524},
      year = {2021},
      doi = {10.1007/s10623-022-01139-8},
      note = {\url{https://eprint.iacr.org/2021/524}},
      url = {https://eprint.iacr.org/2021/524}
}
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