The proxy signature scheme enables a proxy signer to sign messages on behalf of the original signer. Delegating the signature capability of the original signer to a proxy signer has been shown to be useful in many applications. Recently, Seo and Lee proposed a modification to the Park and Lee's nominative proxy signature scheme for mobile communication such that the original signer enables a proxy signer to nominate the verifier. However, the original signer can generate a valid nominative proxy signature without the proxy signer's knowing. In this paper, we show that Seo and Lee's modification is insecure against the original signer's forgery attack, and then propose an improved scheme to repair the security flaw.
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机译：代理签名方案使代理签名者可以代表原始签名者对消息进行签名。将原始签名者的签名功能委托给代理签名者已被证明在许多应用程序中很有用。最近，Seo和Lee提出了针对Park and Lee的用于移动通信的名义代理签名方案的修改，以使原始签名者能够使代理签名者提名验证者。但是，原始签名者可以在不知道代理签名者的情况下生成有效的名义代理签名。在本文中，我们证明了Seo和Lee的修改对原始签名人的伪造攻击是不安全的，然后提出了一种改进的方案来修复安全缺陷。
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