对一种VMSS方案的分析与改进

ANALYSIS AND IMPROVEMENT ON A VERIFIABLE MULTI-SECRET SHARING SCHEME

多秘密共享方案是指一次可共享多个秘密的秘密共享方案。Massoud Hadian Dehkordi和Samaneh Mashhadi提出了一个有效的可验证多秘密共享方案(DM-VMSS)。该方案无需安全通道,且各参与者自己选择各自的秘密份额,故无需验证秘密分发者的诚实性。对DM-VMSS方案进行了安全性分析,首先指出该方案的一个安全缺陷,即:秘密分发者虽无法通过伪造各参与者的秘密份额进行欺骗,但可通过公开无效的函数值使得参与者恢复无效的秘密,而对秘密分发者的这种行为参与者无法察觉。然后对原方案进行改进,在验证阶段加入可检验出秘密分发者的欺骗行为的验证方程,以避免上述安全缺陷和攻击。

Multi-secret sharing scheme is a secret sharing scheme in which several secrets can be shared during one secret sharing process.Massoud Hadian Dehkordi and Samaneh Mashhadi proposed an efficient threshold verifiable multi-secret sharing scheme.We call it DM-VMSS.In this scheme,there is no need for a secure channel and each participant chooses her/his secret share by her/himself.So the honesty of the dealer is Absolutely free from validation.In this paper we analyze the security of DM-VMSS scheme.First,we point out a secure flaw in this scheme,that is,although the dealer couldn＇t become a cheater by falsifying secret shares of each participant,he can publish ineffective function value and which can lead the participants to recover an invalid secret but not be aware of such action of the dealer.Then,we provide an improvement on the scheme to avoid the secure limitation and attacks by adding a validation equation to DM-VMSS scheme in validating phase which is capable of detecting the deceived action of the dealer.