Weighted threshold secret sharing schemes
In a secret sharing scheme, each participant receives a share of a secret in such a way that only authorized subsets can reconstruct the secret. The information rate of a secret sharing scheme is the ratio between the size of the secret and the size of the shares given to the participants. In a weighted threshold scheme each participant has his or her own weight. A subset of participants is authorized to reconstruct the secret if the sum of their weights is greater than or equal to the threshold. This paper deals with weighted threshold schemes, mainly the properties related to the information rate. A complete characterization of the access structures of weighted threshold schemes when all the minimal authorized subsets have at most two elements is presented. Lower bounds for the optimal information rate of these access structures are given. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
secret sharing information rate weighted schemes cryptography