一种改进的定向代理签名方案

An ImprovedDesignated-Receiver Proxy Signature Scheme

在通常的代理签名方案中,任何人都可以验证代理签名的有效性。在定向代理签名方案中,由原始签名人指定一个人作为签名的接收者,以此来防止签名的滥用。当代理签名人产生签名后,只有指定的接收者可以对签名进行验证,进而接受签名。分析了Dai等定向代理签名方案,它不满足不可伪造性,即原始签名人可以成功伪造代理签名人的代理签名。为此,提出了改进的定向代理签名方案,该方案具有不可伪造性,从而有效地防止原始签名人对代理签名人进行恶意攻击,并将其推广到代理多签名方案中。

In ordinary proxy signature schemes, everyone can verify the validity of proxy signature. While in a designated- receiver signature scheme, to avoid the misuse d proxy signatures, an orig- inal signer nominates a person as the signature receiver. As a result, only the person nominated can verify and accept the signature after the proxy signer generating a valid proxy signature on behalf d the original signer. In this paper, we show the designated - receiver proxy signature scheme in Dai et al. [ 10]is insecure against the original signer＇s forgery. That is,their scheme does not satisfy the unforgeability property, which is a desired security requirement of a proxy signature scheme. In addition, we present a modified designated- receiver proxy signature scheme with unforgeability, which will efficiently prevent an original signer from malicious attacks. Then we extend the proposed idea into proxy multi - signature scheme.