Hwang, Lu and Lin (2003) proposed a (t, n) threshold proxy signature scheme, based on the RSA cryptosystem. Later, Wang et al. (2004a) indicated that this scheme was insecure because the original signer's private key could be derived. Moreover, the delegates' identities had to be chosen carefully. In this paper, we propose an improved RSA-based (t, n) threshold proxy signature scheme, which withstands this security flaw and also offers the convenience of choosing identities at will.
International Journal of Information and Computer Security 1(1/2):201-209