Paper 2024/521

LIT-SiGamal: An efficient isogeny-based PKE based on a LIT diagram

Tomoki Moriya, University of Birmingham

In this paper, we propose a novel isogeny-based public key encryption (PKE) scheme named LIT-SiGamal. This is based on a LIT diagram and SiGamal. SiGamal is an isogeny-based PKE scheme that uses a commutative diagram with an auxiliary point. LIT-SiGamal uses a LIT diagram which is a commutative diagram consisting of large-degree horizontal isogenies and relatively small-degree vertical isogenies, while the original SiGamal uses a CSIDH diagram. A strength of LIT-SiGamal is efficient encryption and decryption. QFESTA is an isogeny-based PKE scheme proposed by Nakagawa and Onuki, which is a relatively efficient scheme in isogeny-based PKE schemes. In our experimentation with our proof-of-concept implementation, the computational time of the encryption of LIT-SiGamal is as efficient as that of QFESTA, and that of the decryption of LIT-SiGamal is about $5$x faster than that of QFESTA.

Available format(s)
Public-key cryptography
Publication info
isogeny-based cryptographyKani's theorempublic key encryption
Contact author(s)
t moriya @ bham ac uk
2024-04-06: approved
2024-04-02: received
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      author = {Tomoki Moriya},
      title = {{LIT}-{SiGamal}: An efficient isogeny-based {PKE} based on a {LIT} diagram},
      howpublished = {Cryptology ePrint Archive, Paper 2024/521},
      year = {2024},
      note = {\url{}},
      url = {}
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