Paper 2022/127

CCA secure ElGamal encryption over an integer group where ICDH assumption holds

Gyu-Chol. Kim, Jae-Yong. Sin, and Yong-Bok. Jong

Abstract

In order to prove the ElGamal CCA (Chosen Ciphertext Attack) security in the random oracle model, it is necessary to use the group (i.e., ICDH group) where ICDH assumption holds. Until now, only bilinear group where ICDH assumption is equivalent to CDH assumption has been known as the ICDH group. In this paper, we introduce another ICDH group in which ICDH assumption holds under the RSA assumption. Based on this group, we propose the CCA secure ElGamal encryption. And we describe the possibility to speed up decryption by reducing CRT (Chinese Remainder Theorem) exponents in CCA secure ElGamal.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint. MINOR revision.
Keywords
ElGamalCCA securityrandom oracleRSA
Contact author(s)
kgc841110 @ star-co net kp
History
2022-02-09: received
Short URL
https://ia.cr/2022/127
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2022/127,
      author = {Gyu-Chol. Kim and Jae-Yong. Sin and Yong-Bok. Jong},
      title = {CCA secure ElGamal encryption over an integer group where ICDH assumption holds},
      howpublished = {Cryptology ePrint Archive, Paper 2022/127},
      year = {2022},
      note = {\url{https://eprint.iacr.org/2022/127}},
      url = {https://eprint.iacr.org/2022/127}
}
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