定期更新防欺诈的秘密共享方案

(k,n)门限秘密共享方案是在n个参与者中共享秘密K的方法，以这个方法，任何k个参与者都能计算出K的值，但少于k个参与者就不能计算出K的值，它在实际当中有广泛的应用，该文利用离散对数问题的难解性，提出了一个定期更新防欺诈的(k,n)，门限秘密共享方案，它在保持共享秘密不变的情况下定期对子秘密进行更新，每个参与者可以对自己的子秘密及其他成员出示的子秘密进行验证，不但能有效阻止敌手窃取秘密或子秘密，也能有效地防止内部成员之间的互相欺诈，由于该方案在初始化阶段和子秘密更新阶段始终有一位值得信赖的分发者参与，从而减少了数据传输量和总计算量。

A Secret Sharing Scheme with Periodic Renewing to Identify Cheaters

A (k,n) threshold secret sharing scheme is a method of sharing a secret K among a set of n participants,in such a way that any k participants can compute the value K , but no group of k 1 participants can do so. It has found wide applications in practice. By means of the intractability of discrete logarithm problem, a (k,n) threshold secret sharing scheme with periodic renewing to identify cheaters is proposed. Shares are periodically renewed without changing the secret. Every participant is able to verify the share he receives and those other participants show. This scheme can prevent adversaries from getting the secret or shares and the participants cheating each other efficiently. Because a trusted dealer distributes the secret information in the initialization phase and renewing phases, the amount of data transmitted and calculation time are reduced.