Understanding Intrinsic Characteristics and System Implications of DAG-based Blockchain

Abstract

Blockchain is starting to be deployed in industries by enabling Internet of Things (IoT) for autonomous deviceto-device transactions through distributed blockchain-based immutable ledger technology. However, traditional block-based blockchain techniques, such as Bitcoin and Ethereum, are not suitable for IoT transactions due to its low throughput, high computation overhead, and costly transaction fee. To satisfy the requirements of IoT, DAG-based approaches, aiming to provide cheap blockchain services with low latency and high throughput, are emerging. In this paper, we present a set of comprehensive experimental studies on IOTA, a representative DAG-based blockchain, and aim to exhibit its unique characteristics mainly from two aspects: performance and security. We have developed a series of benchmark tools and judiciously selected typical configurations to perform experimental examinations with a real private IOTA network. Our studies reveal several interesting findings: 1) The throughput of IOTA is higher than the traditional block-based blockchain, but far less than the reported thousands TPS in its whitepaper, even with scaling-up configurations; 2) The database query heavily impacts the performance of IOTA, even more than its PoW (Proof of Work) process. We make our benchmark tools in public and expect our works can inspire system architects, application designers, and practitioners with new optimization directions and potential application cases for further exploration.