基于ElGamal密码体制的可验证秘密共享方案

基于ElGamal密码体制,提出了一个新的可验证秘密共享方案.方案中,秘密份额由各个参与者自己选择,秘密分发者不知道各个参与者所持有的份额,而且秘密份额长度与共享秘密长度相同.重构秘密时,任一参与者只需计算一次即可确认参与者中是否存在欺诈者,欺诈成功的概率可忽略不计.若存在欺诈者,则可通过秘密分发者来确定欺诈者身份.该方案具有充分的秘密信息利用率和较少的验证计算量.当共享秘密更换时,参与者不必更换自己的秘密份额.并且,每个参与者只需维护一个秘密份额,就可以实现对多个秘密的共享.方案的安全性是基于ElGamal密码体制和Shamir门限方案的安全性.

Verifiable Secret Sharing Scheme Based on ElGamal Cryptosystem

Based on ElGamal cryptosystem, a new verifiable secret sharing scheme was proposed. In this scheme, each participant's secret shadow is selected by the participant himself and even the secret dealer does not know anything about his secret shadow. All these shadows arc as short as the secret to be shared. In the recovery phase, any participant computes only one time in order to detect if cheats exist and the probability of successfully cheating can be ignored. The secret dealer can point out the identity of cheats if they exist. For this scheme, the secret information is fully used and the computation complexity of verifying can be reduced largely. The shadows do not need to be changed when the shared secret is renewed. Moreover, each participant can share many secrets with other participants by holding only one shadow. The security of this scheme is the same as that of the ElGamal cryptosystem and Shamir's (t,n) threshold secret sharing scheme.