Remarks on Wu-Hsu's threshold signature scheme using self-certified public keys

Wu and Hsu proposed a (t, n) threshold signature scheme using self-certified public keys in order to integrate the properties of self-certified public key schemes and threshold signature schemes. Even though their scheme is more efficient when compared to previous works based on the certificate-based public key systems, we find some design defects of their scheme. In this paper, by identifying some concrete instances and analyses we will show that their scheme is not as secure as they claimed.