Tightly Secure Public-Key Encryption with Equality Test Supporting Flexible Authorization in the Standard Model

11 pages•Published: August 21, 2025

Yi-Fan Tseng, Yi-Jiin Lu, Tien-Lin Tsai and Zi-Yuan Liu

Abstract

We introduce a novel Public Key Encryption with Equality Test supporting Flexible Authorization scheme offering User-Level, Ciphertext-Level, and User-Specific-Ciphertext-Level authorizations. Notably, our construction achieves security under the Decisional Diffie-Hellman assumption with a tight reduction, whereas the existing works are either not tightly secure or rely heavily on the random oracles. By relying solely on the standard DDH assumption, our scheme offers practical implementation without specialized cryptographic structures.

Keyphrases: flexible authorization, public key encryption with equality test, standard model, tight security

In: Akira Yamada, Huy Kang Kim, Yujue Wang and Tung-Tso Tsai (editors). Proceedings of the 20th Asia Joint Conference on Information Security, vol 106, pages 122-132.

Links:	https://easychair.org/publications/paper/5zBD
	https://doi.org/10.29007/f9gd

BibTeX entry

@inproceedings{AsiaJCIS2025:Tightly_Secure_Public_Key,
  author    = {Yi-Fan Tseng and Yi-Jiin Lu and Tien-Lin Tsai and Zi-Yuan Liu},
  title     = {Tightly Secure Public-Key Encryption with Equality Test Supporting Flexible Authorization in the Standard Model},
  booktitle = {Proceedings of the 20th Asia Joint Conference on Information Security},
  editor    = {Akira Yamada and Huy Kang Kim and Yujue Wang and Tung-Tso Tsai},
  series    = {EPiC Series in Computing},
  volume    = {106},
  publisher = {EasyChair},
  bibsource = {EasyChair, https://easychair.org},
  issn      = {2398-7340},
  url       = {/publications/paper/5zBD},
  doi       = {10.29007/f9gd},
  pages     = {122-132},
  year      = {2025}}

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