链上、链下协同的智能合约即服务问题  

Smart contracts-as-a-service with on-chain and off-chain collaboration

作　　者：刘浩宇[1] 马泽祁 叶亚飞 胡凯[1,2] LIU Haoyu;MA Zeqi;YE Yafei;HU Kai(State Key Laboratory of software development,Beihang University,Beijing 100191,China;Yunnan Research Institute of Beihang University,Kunming 650000,China)

机构地区：[1]北京航空航天大学软件开发国家重点实验室,北京100191 [2]北京航空航天大学云南研究院,昆明650000

出　　处：《北京航空航天大学学报》2024年第10期3262-3273,共12页Journal of Beijing University of Aeronautics and Astronautics

基　　金：云南省重大科技专项(202103AN080001-001,202002AA100007,202002AD080003);软件开发国家重点实验室开放基金(SKLSDE-2022ZX-11)。

摘　　要：智能合约是区块链上的一种软件服务,具有价值传导、契约性和可信性等特点,当前各区块链系统上的智能合约数量越来越多,应用范围越来越广泛,传统智能合约的局限性也日益增大。隔离沙箱环境执行使智能合约与外界交互困难、资源受限、从而限制了智能合约的使用场景和性能。同时,传统的云服务等链下服务存在中心化风险,缺乏信任机制保障。提出智能合约即服务方案,提供链上合约与链下服务协同的方法,通过链下服务的链上认证,将服务生命周期纳入区块链管理,使之具有合约服务的可信化特点,以支持服务的注册、定制和组合;提出基于交易触发与事件驱动的通信与协同方法,在面对复杂业务场景或高资源需求任务时智能合约可与扩展服务组合构建工作流。经实验验证表明,智能合约即服务可以极大地拓展合约应用场景,通过将合约内执行的高资源耗费任务卸载到计算型扩展服务可提供更高的性能,性能优势与链下加速比正相关,如在执行1200维矩阵乘法运算的任务时,性能可提升64%。A smart contract is a software service on blockchain with the characteristics of value transfer,contractuality,and trustworthiness.The quantity of smart contracts on blockchain systems is currently rising,together with the application scope's expansion and the restrictions of conventional smart contracts'growing number.Isolated sandbox environment execution makes it difficult for smart contracts to interact with the outside world,and resources are limited,limiting the use scenarios and performance of smart contracts.At the same time,off-chain services have the risk of centralization and lack of trust mechanisms to protect them.We propose a Smart Contract-as-a-Service solution,which provides a method for on-chain contracts to collaborate with off-chain services.Through on-chain authentication of off-chain services,the service lifecycle is incorporated into blockchain management,so that it has the trustworthy characteristics of contract services and supports the registration,customization and combination of services.We proposes a communication and collaboration method based on transaction triggering and event-driven mechanisms,where smart contracts can be combined with extended services to construct workflows in the face of complex business scenarios or tasks with high resource demands.Empirical verification demonstrates that Smart Contracts-as-a-Service can significantly expand contract application scenarios and boost performance by shifting resource-intensive tasks from within the contract to computational extension services.The benefit of increased performance is positively correlated with the off-chain speedup ratio,for example,a 64%improvement in performance when performing multiplication of a 1200-dimensional matrix.

关 键 词：智能合约 智能合约即服务 链上、链下协同 服务认证 事件驱动 

分 类 号：O213.2[理学—概率论与数理统计] V37[理学—数学] TP302.1[航空宇航科学与技术—航空宇航推进理论与工程]