Abstract: Admission control is the process of mediating every request to admittance and determining whether the request should be granted or denied.This paper presents a dynamic threshold admission control scheme.This scheme changes the threshold （t） by changing the order （t-1） of the secret polynomial f（z） to make the threshold scale with the number of members in the network.In this way，it solves the problem which can’t change the threshold neatly.The scheme not only can audit a new node according to secure requirements and eliminate undesired nodes for P2P networks，but also withstand conspiracy attack that exists in Kim et al’s schemes.

Key words: threshold signature, threshold, secret sharing, dynamic threshold

摘要： 准入控制是仲裁加入申请是否被批准的一个过程。提出一种动态门限准入控制方案即通过改变秘密多项式f（z）的阶t-1达到改变门限值t，使门限值随着网络规模大小化，从而解决了不能灵活改变阀值的局限性。该方案不仅能根据安全需求对节点进行资格审核，屏蔽掉一些不符合安全要求的节点，而且能抵抗Kim等人方案中存在的合谋攻击。

关键词: 门限签名, 门限值, 秘密共享, 动态门限