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

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

Paper 2025/1213

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

Yi-Fan Tseng

, National Chengchi University

Yi-Jiin Lu, National Chengchi University

Tien-Lin Tsai, National Chengchi University

Zi-Yuan Liu, National Central University

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.

Note: It is the full version of the paper accepted by AsiaJCIS.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Published elsewhere. Major revision. AsiaJCIS 2025
Keywords: Public-Key Encryption with Equality Test Flexible Authorization Standard Model Tight Security
Contact author(s): yftseng @ g nccu edu tw
History: 2025-07-07: approved; 2025-06-30: received; See all versions
Short URL: https://ia.cr/2025/1213
License: CC BY-NC-SA

BibTeX

@misc{cryptoeprint:2025/1213,
      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},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/1213},
      year = {2025},
      url = {https://eprint.iacr.org/2025/1213}
}