A study on the fast ElGamal encryption

Kim Gyu-Chol; Li Su-Chol

Paper 2018/930

A study on the fast ElGamal encryption

Kim Gyu-Chol and Li Su-Chol

Abstract

ElGamal cryptosystem is typically developed in the multiplicative group ( is a prime number), but it can be applied to the other groups in which discrete logarithm problem should be computationally infeasible. Practically, instead of ElGamal in , various variants such as ECElGamal (ElGamal in elliptic curve group), CRTElGamal (ElGamal in subgroup of where and are primes) have already been used for the semantic security. In this paper, for the fast decryption, we reduced the private CRT exponent () and ()maintaining full sized private exponent () in CRTElGamal as reducing () and () in RSA for the fast decryption. (i.e. as in rebalanced RSA). In this case, unlike rebalanced RSA, decryption of CRTElGamal can be done faster without losing of encryption speed. As a result, it is possible to propose the fast public key cryptosystem that has fast encryption and fast decryption.

Metadata

Available format(s): PDF
Category: Public-key cryptography
Publication info: Preprint. MINOR revision.
Keywords: RSA ElGamal public key Rebalanced RSA CRT
Contact author(s): kgc841110 @ star-co net kp
History: 2018-10-02: received
Short URL: https://ia.cr/2018/930
License: CC BY

BibTeX

@misc{cryptoeprint:2018/930,
      author = {Kim Gyu-Chol and Li Su-Chol},
      title = {A study on the fast {ElGamal} encryption},
      howpublished = {Cryptology {ePrint} Archive, Paper 2018/930},
      year = {2018},
      url = {https://eprint.iacr.org/2018/930}
}