最近杨宇光等人利用经典秘密共享给出一系列量子密码方案.其基本思想是将量子密钥共享给n个不同的成员,使得这些成员可以辅助实现量子身份认证、代理签名和量子安全直接通信.然而在实际应用中,这些方案继承了经典秘密共享方案的缺点,不能提供每个成员诚实参与协议的证明,任何恶意不合作行为只有最后才能被发现,从而使这类量子密码方案的使用效率很低.其次,由于这些方案使用了比特异或运算,使方案还存在一个更严重的攻击:如果任意两个成员合谋,可以改变他们原有的影子值,并且可以无障碍的使用新的影子参与量子密码方案,破坏协议执行的目的,使方案的门限彻底失效.此攻击是量子密码方案除密钥安全外的一种新的攻击形式. Recently, Yang Yuguang and his colleagues used classical secret sharing to give a series of quantum cryptography schemes, whose basic idea is to share the quantum key to n different members so that these members can assist in the realization of quantum identity authentication, proxy signature and quantum security direct communication. However, in practice, these programs inherit the shortcomings of the classical secret sharing scheme, can not provide each member to prove honest participation in the agreement, any malicious uncooperative behavior can only be found in the end, so that the use of such quantum cryptography is very efficient Second, because these schemes use bitwise XOR, there is a more serious attack on the scheme: if any two members collude, they can change their original shadow values ​​and can use the new shadow for accessibility Quantum cryptography, which undermines the purpose of protocol implementation, completely invalidates the threshold of the scheme, which is a new form of attack besides quantum cryptography besides key cryptography.