有效的门限签名算法

Efficient threshold signature scheme

门限签名是一种特殊的数字签名,它在现实生活中具有广泛的用途。一个(t,n)门限签名方案是指n个成员组成的群中,群中任何不少于t个成员合作就能产生签名,然而任何少于t个成员合作都无法伪造签名。但是,现有的许多签名算法都存在一个普遍的缺陷,即不能抵抗合谋攻击,换句话说,任意t个成员合谋就可以恢复出秘密系统参数,从而就可以伪造其他签名小组签名。针对较小的n和t以及较大n和t分别提出两种有效的抗合谋攻击的门限签名方案,当n和t较小时,给出了一种基于分组秘密共享的RSA门限签名算法;当n和t比较大时,提供了一种具有指定签名者的方案来解决合谋攻击问题。

Threshold signature is a special digital signature,and it is in popular use.A t out of n threshold signature scheme is a protocol that only t or more than the threshold number group members can generate a valid signature , while fewer than t players cannot create a valid signature in the protocol.But most Of the recent protocols cannot withstand conspiracy attacks.In other words,in most of t protocols,some subgroups of t or more than t players can easily get any secret parameters of the system,so any subgroups of t players can forge any valid signature in place of other subgroups.In this paper,we introduce two methods to withstand conspiracy attacks：when n and t are not very large,we present an efficient threshold RSA signature scheme.Furthermore we also introduce a kind of method that can be applied in any threshold signature schemes so that the resulting scheme can withstand conspiracy attacks when n and t are large.