Key recovery attack on Hufu-UOV

Abstract

The unbalanced oil and vinegar signature scheme (UOV) is a signature scheme whose public key is a set of quadratic polynomials over a finite field. This scheme has been considered to be secure and efficient enough under suitable parameter selections. However, its key size is relatively large, and then various arrangements of UOV with smaller keys have been proposed. Hufu-UOV proposed by Tao in 2019 is one of such variants of UOV, whose keys are generated by circulant and Toeplitz matrices. In the present paper, we study the security of Hufu-UOV and propose an attack on it.