利用一类特殊多项式构造了一种(k,n)-门限体制。该体制能够由成员自主地选择子密钥,因此在应用上更加灵活方便。而且在系统更新时,增删成员时,无须更改子密钥,因此每个成员的子密钥可以多次使用。另外该方案又是可验证的,从而可以有效的阻止来自系统内部和外部的攻击,提高了系统的实用性。 A kind of special polynomial is used to construct a (k, n) - threshold system. The system can choose sub-keys autonomously by members, so it is more flexible and convenient in application. And when the system is updated, add or delete members, no need to change the sub-key, so each member’s sub-key can be used more than once. In addition the program is verifiable, which can effectively prevent attacks from inside and outside the system, improving the system’s practicality.