Distributed Storage Meets Secret Sharing on the Blockchain

Abstract

Blockchain systems establish a cryptographically secure data structure for storing data in the form of a hash chain. We use a novel combination of distributed storage, private key encryption, and Shamirs secret sharing scheme to distribute transaction data, without significant loss in data integrity. Additionally, using Shamirs secret sharing scheme on the hash values and dynamic zone allocation, we further enhance the integrity. We highlight the tradeoff in storage cost and data loss probability with varying zone size choices. We also study the tradeoff between recovery cost and security from adversarial corruption with varying recovery mechanisms. Then, we formulate code design, given a probability of data recovery and targeted corruption, as an integer program. Using the coding scheme we establish a mechanism to insure data, for instance in blockchain-based cloud storage systems, based on the value of the data, by understanding the costs involved for the service provider.