Practical Mobile Proactive Secret Sharing

Abstract

Secret sharing schemes are needed to store and protect secrets in large scale distributed systems. These schemes protect a secret by dividing the it into shares and distributing the shares to multiple shareholders. This way the compromise of a single shareholder does not reveal the secret. Many new secret sharing schemes, such as Proactive Secret Sharing, have been developed to combat the increasing threat from malicious nodes and keep systems secure. However, most of these schemes can be compromised over time, since share transfer and redistribution are static: the set of shareholders is fixed. Mobile Proactive Secret Sharing (MPSS) is a new protocol with dynamic redistribution that can adapt to Byzantine faults and remain secure for the duration of long-lived systems. This thesis describes the simulation, testing, and evaluation of the MPSS protocol to better understand the performance trade-offs and practicality of secret sharing protocols operating in Byzantine faulty environments. The thesis evaluates the original MPSS scheme and the MPSS scheme with verifiable accusations in a distributed setting, finds that both schemes are practical, and explores the performance trade-offs between the two schemes.