几个提名代理签名方案的安全分析

在提名代理签名中，原始签名方将签名权利委托给代理签名方，这时代理签名方还充当着提名者的角色，代理签名方（提名方）代表原始签名方产生提名签名，随后将生成的提名代理签名传递给被提名方加以验证．在提名代理签名中，除了要求具有代理签名的性质，还应有提名签名的性质，即提名性：仅有被提名者可以验证一个提名代理签名有效与否，而且如果必要，仅有被提名方可以向第三方证实这个代理提名签名有效与否．文章按照提名代理签名应满足的条件分析了Zhang等的方案．指出这些方案不满足提名性．在Zhang等的方案中，提名方也可以验证一个提名代理签名有效与否，而且也可以向第三方证实其有效性．

The Security of Some Nominative Proxy Signature Schemes

In a nominative proxy signature, an original signer delegates the slgnmg rlght to a proxy signer. At this time, the proxy signer plays the role of the nominator. The proxy signer （nominator） generates a nominative signature on behalf of the original signer. Then,he transmits the proxy nominative signature to the nominee to verify it. In a nominative signature,besides re- quiring the property of proxy signature,the nominative signature also has nominative property. That is, only the nominee can verify the nominative proxy signature valid or not, if necessary, only the nominee can confirm that signature valid or not to the third party. According to satisfying the conditions for nominative signature, this paper analyzes Zhang et al. scheme. We point out that these schemes do not satisfy nominative property. In Zhang et al. scheme,nominator also can veri- fy a nominative signature valid or not and confirm the nominative signature valid or not.