Strategies of Proactive (k, n) Threshold Secret Sharing and Applications in a Secure Message Exchange System

Abstract

A secret sharing scheme protects the secret by distributing it to a group of participants (nodes), and it allows for some groups of participants to collaborate together to reconstruct this secret. With regard to the (k, n) threshold scheme, k out of n or more participants can reconstruct the secret. The proactive secret sharing scheme periodically updates the distributed secret (shadow). Based on such a proactive secret sharing scheme, we propose a completely mobile proactive secret sharing scheme, which not only allows for the changing of participant number n, but also arbitrarily changes the threshold k. Furthermore, we apply our technical idea to a specified project exploitation in the real commerce transaction systems to fulfill a trust-based delivery.