Security issues of CFS-like digital signature algorithms

TL;DR

This paper examines security vulnerabilities in variants of the CFS code-based digital signature scheme, revealing that certain efficiency improvements introduce forgery risks due to code-based hash-function adoption.

Contribution

The study identifies specific security flaws in CFS-like schemes caused by the use of code-based hash-functions for efficiency, highlighting potential forgery attacks.

Findings

Adoption of code-based hash-functions can enable forgeries.

Certain CFS variants are vulnerable to forgery attacks.

Efficiency improvements may compromise security.

Abstract

We analyse the security of some variants of the CFS code-based digital signature scheme. We show how the adoption of some code-based hash-functions to improve the efficiency of CFS leads to the ability of an attacker to produce a forgery compatible to the rightful user's public key.