LBFT-DAG: A Swift, Leader-Driven, DAG-Based Consortium Blockchain with Byzantine Fault-Tolerance

Due to their parallel processing capabilities across different nodes, Directed Acyclic Graph (DAG) based blockchains have emerged as promising alternatives to traditional blockchains with a single-chain structure. However, existing DAG ledgers mostly have complex structures and rely on resource-intensive consensus protocols (e.g., PoW) to establish a stable main chain and determine the total order of all blocks. Moreover, they require a certain number of voting or successive PoW-like confirmations for each new block, resulting in significant delays. To tackle above issues, this paper proposes LBFT-DAG, the first Leader-drtven, Byzantine Fault- Iolerant, DAG-based consortium blockchain. In LBFT-DAG, a concise ledger consists of the leader node's main subchain and several normal nodes' parallel subchains, where each block only refers to the preceding blocks in two subchains. To quickly establish the total order of the ledger, we present a two-stage ordering algorithm following the principle of the main subchain first. Additionally, an asynchronous, Byzantine Fault-tolerant voting process on only leader blocks is designed to smoothly achieve security for all blocks. Extensive analysis confirms the security of LBFT-DAG, and experimental results demonstrate that LBFT-DAG achieves about four times higher transaction throughput on average compared to state-of-the-art solutions.