A New (k,n)-Threshold Secret Sharing Scheme and Its Extension

Abstract

In Shamir's (k,n)-threshold secret sharing scheme (threshold scheme), a heavy computational cost is required to make nshares and recover the secret. As a solution to this problem, several fast threshold schemes have been proposed. This paper proposes a new (k,n)-threshold scheme. For the purpose to realize high performance, the proposed scheme uses just EXCLUSIVE-OR(XOR) operations to make shares and recover the secret. We prove that the proposed scheme is a perfectsecret sharing scheme, every combination of kor more participants can recover the secret, but every group of less than kparticipants cannot obtain any information about the secret. Moreover, we show that the proposed scheme is an idealsecret sharing scheme similar to Shamir's scheme, which is a perfectscheme such that every bit-size of shares equals that of the secret. We also evaluate the efficiency of the scheme, and show that our scheme realizes operations that are much faster than Shamir's. Furthermore, from the aspect of both computational cost and storage usage, we also introduce how to extend the proposed scheme to a new (k,L,n)-threshold rampscheme similar to the existing rampscheme based on Shamir's scheme.