Performance evaluation of isogeny-based digital signature algorithms: introducing FIBS-fast isogeny-based digital signature

Abstract

Constructing a digital signature scheme is considerably more challenging to accomplish than a key exchange in isogeny-based cryptography. Except for SQISign, other isogeny-based digital signature algorithms 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 diverse isogeny-based digital signature scheme that is robust enough to 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. Targeting NIST security level 1, our implementation in C with CGL hash function instantiated with 256-bit prime takes 38.08 s for key generation, 896.39 s for signing, and 172.37 s for verification. To provide a comprehensive evaluation, we compared FIBS with other isogeny-based digital signatures and selected digital signatures from the NIST PQC standardization project, analyzing performance and memory usage using Valgrind. The results demonstrate that FIBS offers “moderately fast and efficient" performan