Secure Regenerating Codes for Reducing Storage and Bootstrap Costs in\n Sharded Blockchains

Abstract

Blockchain is a distributed ledger with wide applications. Due to the\nincreasing storage requirement for blockchains, the computation can be afforded\nby only a few miners. Sharding has been proposed to scale blockchains so that\nstorage and transaction efficiency of the blockchain improves at the cost of\nsecurity guarantee. This paper aims to consider a new protocol,\nSecure-Repair-Blockchain (SRB), which aims to decrease the storage cost at the\nminers. In addition, SRB also decreases the bootstrapping cost, which allows\nfor new miners to easily join a sharded blockchain. In order to reduce storage,\ncoding-theoretic techniques are used in SRB. In order to decrease the amount of\ndata that is transferred to the new node joining a shard, the concept of exact\nrepair secure regenerating codes is used. The proposed blockchain protocol\nachieves lower storage than those that do not use coding, and achieves lower\nbootstrapping cost as compared to the different baselines.\n