Comparative Evaluation of Quantum-Resistant Digital Signatures

In this work we implemented and evaluated the performance of the most relevant pre-quantum, post-quantum (PQC) and quantum digital signature (Q-DS) algorithms during the key generation, signature generation and signature verification processes. The aim is to help in the selection of possible candidates during the migration process from current cryptographic systems to quantum-resistant ones. As a result, for a security level of 256 bits, RSA is the pre-quantum algorithm that presents the worst performance together with the “small” variant of SPHINCS+ sphincsshake256ssimple in PQC. The Q-DS is the most efficient solution during the signature generation and verification, but its performance is strongly impacted in the key generation process that is carried out through Quantum Key Distribution. The out-performer within the pre-quantum algorithms, for a security level of 256 bits, is the elliptic curve secp521r1 and within PQC solutions the CRYSTALS-Dilithium DSA Dilithium5 stands out.