Multilevel Threshold Secret Sharing using the Chinese Remainder Theorem

Özet

In multilevel secret sharing, a secret is shared among a set of hierarchically organized participants in a way that the members of the superior compartments are more powerful and can replace the participants of an inferior one to form an authorized coalition during secret reconstruction. In this work, we first show that the only existing multilevel threshold secret sharing scheme based on the Chinese Remainder Theorem (CRT) is not secure and fails to work with certain natural threshold settings on compartments. As the main contribution, we propose a secure CRT-based scheme that works for all threshold settings. In the proposed scheme, we employ a refined version of Asmuth-Bloom secret sharing with a special and generic Asmuth-Bloom sequence called the anchor sequence.