BSS: An Efficient Block Storage System for Block Archive Service in Blockchains.

While blockchain enables decentralized services with zero trust, every node needs to store continuously generating block information in their local storage. Because blocks are generating continuously in blockchain, there exists a significant storage space burden on each node. A typical technique is to introduce a special node customized for block archiving. In case of Ethereum, a special node called block archive node to store all historical blocks. With the help of block archive node, each full node is enough to maintain only latest 128 blocks. In this paper, we propose BSS, an efficient block storage system for block archive service in blockchains, which can support any blockchain including Ethereum. BSS is a distributed system consisting of some number of block archive nodes. The storage overhead of BSS is O(1). The main idea is to encode each block into several small chunks and enforce each archive node to store one chunk, not an entire block. BSS also supports Byzantine tolerant chunk storage protocol for possible Byzantine attacks by block archive nodes. It is shown from the experiments on AWS, BSS enables both substantial block availability and notable performance even in Byzantine attacks.