ESS: An Efficient Storage Scheme for Improving the Scalability of Bitcoin System

Abstract

With the continuous development of blockchain technology, Bitcoin as the first cryptocurrency has drawn massive attention from various sectors. A full node on Bitcoin network has to store over 320GB of data as of March 9, 2021. According to the growth rate of Bitcoin transactions, it is estimated that the size of Bitcoin data on a full node will exceed 400GB within two years. The storage problem makes it difficult for common users to easily store all of Bitcoin data, which weakens the decentralization capability of Bitcoin network. In this work, we propose an efficient storage scheme (ESS) based on the distribution characteristics of the unspent transaction outputs in Bitcoin system. It can prune the storage of the transactions for those low query frequency blocks. When a new block is generated, a node using ESS scheme can quickly verify most of the transaction inputs. Only a small amount of transaction outputs of older blocks need to be retrieved from the full node for payment verification. Experimental results demonstrated that our scheme can reduce the size of a normal node in current Bitcoin system by about 85% at a low communication cost.