Performance Evaluation of Isogeny-Based Digital Signature Algorithms : Introducing FIBS -- Fast Isogeny Based Digital Signature

Abstract

Abstract Constructing a digital signature scheme is considerably more challenging to accomplish than a key exchange in isogeny-based cryptography. Currently, SeaSign, CSI-FiSh, and SQISign are well-known isogeny-based digital signature algorithms, but most of them, except SQISign, are considered impractical primarily due to performance reasons. However, an even more significant concern lies in security issues. Recently, various quantum and non-quantum attacks, including Castryck and Decru's brilliant method, have been proposed to break isogeny-based cryptosystems. Therefore, there is a need for a more efficient isogeny-based digital signature scheme that is robust enough to simultaneously withstand emerging attacks.This paper presents FIBS: Fast isogeny-based digital signature based on the isogeny-based hash function. We combine the CGL hash function and SPHINCS+ -- a hash-based digital signature algorithm. For a 128-bit quantum security level, our implementation in C takes 121.66s for key generation, 2837.04s for signing, and 172.37s for verification. The use of the CGL hash function, which is still considered to be secure, along with the conservative nature of hash-based digital signatures, contributes to our proposal.