Alias-Chain: Improving Blockchain Scalability via Exploring Content Locality among Transactions

A Blockchain is a promising infrastructure but it has serious scalability problems, i.e., long block synchronization time and high storage cost. Conventional coarse-grained data deduplication schemes (block or file level) are proved to be ineffective on this problem. Based on comprehensive analysis on typical blockchain workloads, we are the first to propose two new locality concepts: economic and argument locality. To further explore these new localities, we propose a novel fine-grained data deduplication scheme (transaction level) named Alias-Chain to improve the scalability of blockchains. Specifically, Alias-Chain replaces frequently used data, e.g., smart contract arguments, with much shorter aliases to reduce the block size. During prop-agation and preservation of blocks, smaller blocks result in both shorter synchronization time and lower storage cost. Simulation results show the average transfer and SC-call transaction sizes can be reduced by up to 11.23% and 43.23% in native Ethereum, and up to 61.95 % and 77.54 % in Ethereum optimized by state-of-the-art techniques, respectively. Prototyping-based experiments are further conducted on a testbed consisting of up to 3200 miners. The results demonstrate the effectiveness and efficiency of Alias-Chain on reducing block synchronization time and storage cost under typical real-world workloads.