After analyzing a proxy blind signature scheme proposed by Yang et al.,it was pointed out that the scheme was insecure against the original signer’s forgery attack, need the support of the secure channel. To overcome the security problems existing in Yang's scheme,an improved proxy signature scheme was proposed. The new scheme resolved forgery attack in the former scheme and met the security requirement of proxy signature scheme, did not need the support of the secure channel.The analytical results prove that the new scheme is mo...
