Coding for Scalable Blockchains via Dynamic Distributed Storage

Abstract

Blockchains store transaction data in the form of a distributed ledger where each node in the network stores a current copy of the sequence of transactions as a hash chain. This requirement of storing the entire ledger incurs a high storage cost that grows undesirably large for high transaction rates and large networks. In this work we use secret key sharing, private key encryption, and distributed storage to design a coding scheme such that each node stores only a part of each transaction, thereby reducing the cold storage cost to a fraction of its original cost. In addition, the storage code ensures the security of the storage from active adversaries that may aim to corrupt prior transactions by altering copies of the ledger. We further employ a dynamic zone allocation algorithm that spreads the node allocation and data distribution across transactions. Under this coding scheme we show that we can also improve the integrity of the transaction data in the network over current schemes.