A New Group-based Secret Function Sharing with Variate Threshold

Secret sharing is a cryptographic scheme that divides a secret key s to n participants with threshold t. Thus, assuring that no less than t shares can reconstruct the secret. The application of secret sharing also widens not only one group but several hierarchical structure. However, the group-based secret sharing proposed by Liu et al. in 2014 has some drawbacks, which are having an equal threshold for each group and also reconstruct only partial secret when the present groups are less. In this paper, we attempt to apply a group-based hierarchical structure in secret sharing by applying derivation. The proposed scheme is the first approach of combining a hierarchical structure and a group-based secret sharing. The proposed scheme shows a better security than Liu et al. considering the structure of the group. Also, it has variated threshold in each group, which is possible for giving less threshold for high-level participants and more threshold for low-level participants. Keywords—Secret Sharing, Group Access Control, Hierarchical, Variate Threshold Track—Cryptographic Technologies, Secret Sharing.