Back to the Future: Rethinking Endorsement in Order-Execute Blockchains

2026-04-30

AI Summary

This work addresses the high transaction abort rates inherent in traditional Execute-Order-Validate (EOV) architectures within highly competitive DeFi environments, as well as the lack of flexible endorsement mechanisms in existing Order-Execute frameworks. To overcome these limitations, the authors propose FlexTender, which integrates flexible endorsement logic deeply into the Tendermint consensus protocol for the first time within an Order-Execute paradigm. Without requiring system redesign or introducing additional communication overhead on the normal execution path, FlexTender deterministically filters out conflicting transactions during consensus, thereby achieving a balanced trade-off among performance, censorship resistance, and decentralization. Experimental evaluations on the ChainMaker platform under Ethereum USDT workloads demonstrate that FlexTender achieves up to a 10.6× throughput improvement over conventional EOV approaches.

Abstract

Due to regulatory compliance and governance management, modern (permissioned) blockchains require flexible endorsement, which allows the endorsement policy for each contract or state object to be individually defined. To enable flexible endorsement, Hyperledger Fabric employs an execute-order-validate (EOV) paradigm, in which transactions first undergo speculative execution and endorsement, and are only then ordered and validated. Meanwhile, most blockchain systems, including the platform targeted in this work (i.e., ChainMaker), still follow a conflict-free order-execute framework. We argue that the EOV paradigm still faces several limitations, notably high abort rates in high-contention workloads such as those in Decentralized Finance (DeFi). To avoid refactoring our system and better suit DeFi applications, we try to integrate flexible endorsement into the classical order-execute architecture and accordingly propose a new framework. The key challenge is to deterministically remove problematic transactions from an ordered list, while preserving censorship resistance and decentralization for the remaining ones. We instantiate this framework on top of Tendermint, a seminal Byzantine fault-tolerant (BFT) protocol adopted in our system, and thereby propose FlexTender. By elegantly embedding endorsements into consensus, FlexTender incurs no additional messaging overhead in the normal case. Empirical evaluation using an Ethereum USDT workload demonstrates that FlexTender achieves up to $10.6\times$ speedup in throughput over an EOV simulation on the same platform.

Problem

• flexible endorsement
• order-execute blockchain
• transaction abort rate
• DeFi
• censorship resistance

Innovation

• flexible endorsement
• order-execute blockchain
• Tendermint
• Byzantine fault tolerance
• DeFi