Cross-chain transaction plays a pivotal role in enhancing decentralized applications by enabling interactions and executing local transactions across multiple blockchain systems. However, existing methods on its execution often suffer from high latency, primarily due to the sequential order-validate-execute paradigm, where each local transaction is processed only after the preceding ones are committed. This sequential approach slows down the process as it requires sequential commitment steps on involved blockchains. To address these challenges, we propose Turbo, a novel framework that enhances cross-chain transaction execution by adopting an optimistic execution paradigm. Turbo optimizes latency by concurrently ordering transactions without strict dependency sequences and employing advanced validation techniques to ensure sequence consistency. We implemented Turbo on top of the Cosmos network and conducted extensive experimentation. The results demonstrate its practicality in handling cross-chain transaction execution with low latency, marking a substantial improvement over the state-of-the-art.

Directed Acyclic Graph(DAG)-based blockchain represents a paradigm shift from conventional blockchains, which has the potential to drastically improve throughput performance through concurrent storage and executions. In practice, however, existing DAG-based blockchains fail to deliver such promises, often with limited throughput, high conflicts, and security vulnerabilities under dynamic workloads. The root causes are their unawareness of the workload characteristics of different workload sizes and skewed access patterns. In this paper, we propose MorphDAG, the first workload-aware DAG-based blockchain that can significantly enhance throughput without compromising security and achieve elastic scaling under realistic workloads. We derive the theoretically optimal degree of storage concurrency to achieve high throughput while retaining system security as the workload size changes, while enabling fine-grained concurrency adjustment that accommodates aProof-of-Stake(PoS)-based consensus protocol. We develop a dual-mode transaction processing mechanism that effectively resolves the conflicts brought by skewed access. We implement a prototype of MorphDAG and evaluate under real-world workloads. Extensive evaluations demonstrate that MorphDAG improves end-to-end throughput by up to 2.3× and 2.4× over state-of-the-art DAG-based blockchain systems AdaptChain and OHIE, respectively.