A Security Analysis on MQ-Sign

MQ-Sign is a variant of the UOV signature scheme proposed by Shim et al. It has been suggested as a candidate for the standardization of post-quantum cryptography in Republic of Korea (known as KpqC). Recently Aulbach et al. proposed a practical key recovery attack against MQ-Sign-RS and MQ-Sign-SS with a simple secret key \(\mathcal {S}\) . In this paper, we propose another attack that is valid for the case of a general secret key \(\mathcal {S}\) .