LESS-FM: Fine-Tuning Signatures from the Code Equivalence Problem

Code-based cryptographic schemes are highly regarded among the quantum-safe alternatives to current standards. Yet, designing code-based signatures using traditional methods has always been a challenging task, and current proposals are still far from the target set by other post-quantum primitives (e.g. lattice-based). In this paper, we revisit a recent work using an innovative approach for signing, based on the hardness of the code equivalence problem. We introduce some optimizations and provide a security analysis for all variants considered. We then show that the new parameters produce instances of practical interest.