Applying a cryptographic metric to post-quantum lattice-based signature algorithms

Measuring the security of cryptographic systems is not a simple task. Nevertheless, there is an increasing need for a cryptographic metric which could assist in decision making when choosing between various candidates. The National Institute of Standards and Technology (NIST) has launched a process to standardize quantum-resistance public key encryption, key encapsulation and digital signature algorithms. This is NIST's response to the threat posed by quantum computers against classical public key cryptography. In this paper, we apply a metric taxonomy, produced by earlier studies, to two NIST third round finalist digital signature algorithms Dilithium and Falcon in order to asses the effectiveness and extensiveness of the metric. Although, our results show that clear differences can be found with used metrics, we propose some improvements to them to allow more comprehensive analysis.