許蘊韜,朱俊武*,孫彬文,孫茂圣,陳四海
選舉供應鏈:基于區(qū)塊鏈的供應鏈自治框架
許蘊韜1,朱俊武1*,孫彬文1,孫茂圣2,陳四海3
(1.揚州大學 信息工程學院,江蘇 揚州 225127; 2.揚州大學 信息化建設與管理處,江蘇 揚州 225127; 3.阜寧縣自來水有限公司信息中心,江蘇 鹽城 224404)(*通信作者電子郵箱jwzhu@yzu.edu.cn)
區(qū)塊鏈與供應鏈的結合應用是近幾年的熱門研究課題。區(qū)塊鏈的數(shù)據(jù)可溯源、防篡改、分布式存儲等優(yōu)點可以為供應鏈提供較好的數(shù)據(jù)安全保障,而區(qū)塊鏈自身的自治屬性也為供應鏈自治提供了可能。區(qū)塊鏈的自治主要依賴于共識機制,然而現(xiàn)有共識機制難以實現(xiàn)對供應鏈自治的良好支持。針對上述問題,提出一種基于委托權益證明(DPoS)的選舉型共識機制,并在此基礎上構建了一個基于區(qū)塊鏈的供應鏈自制框架:選舉供應鏈(ESC)。在ESC中,先根據(jù)節(jié)點參與的智能合約活動計算其信用分,然后從博弈論的角度分析ESC下節(jié)點的活躍度和信用分數(shù)對其權益的影響。最后,通過定理證明與仿真實驗驗證了該機制對節(jié)點具有良好的激勵作用,能有效抑制理性節(jié)點支付的最大交易費用,且抑制的力度會隨著代表數(shù)量的增加而增大。
供應鏈;區(qū)塊鏈;智能合約;選舉;共識算法;博弈論
傳統(tǒng)供應鏈在數(shù)據(jù)溯源、數(shù)據(jù)安全性、數(shù)據(jù)存儲等方面有較高的要求。區(qū)塊鏈具有數(shù)據(jù)可追溯、數(shù)據(jù)防篡改、分布式存儲等優(yōu)點,引入智能合約后,區(qū)塊鏈的去中心化、去信任等屬性[1]也日益凸顯。此外,區(qū)塊鏈系統(tǒng)表現(xiàn)出較強的自治屬性,這為供應鏈中的自主管理提供了可能。在區(qū)塊鏈及其智能合約的支持下,供應鏈的自動化、自治程度將得到極大提高。
區(qū)塊鏈智能合約最早以比特幣腳本[2]的形式被用于控制簡單的比特幣交易。近年來,隨著以太坊、Hyperledger Fabric等內(nèi)置圖靈完備開發(fā)環(huán)境的區(qū)塊鏈平臺的發(fā)布,智能合約的計算功能得到進一步完善。在區(qū)塊鏈與物聯(lián)網(wǎng)(Internet of Things, IoT)等技術的加持下,傳統(tǒng)供應鏈中的生產(chǎn)、裝配、運輸、倉儲等流程均可利用智能合約實現(xiàn)不同程度的自動化。
近幾年工業(yè)界十分重視IoT-區(qū)塊鏈在供應鏈中的應用。文獻[6]中綜述了區(qū)塊鏈在供應鏈管理中的應用,分析了不同行業(yè)下供應鏈的需求特點與相應的區(qū)塊鏈解決方案;文獻[7]中對IoT-區(qū)塊鏈系統(tǒng)網(wǎng)絡進行了詳盡的調(diào)查分析,列舉并對比了現(xiàn)有IoT-區(qū)塊鏈系統(tǒng)采用的各種共識機制。Filament[8]、UniquID[9]、LeewayHertz[10]等一眾IoT-區(qū)塊鏈產(chǎn)品仍以最成熟、最安全的PoW作為共識機制,但由于IoT設備的計算和存儲能力有限,在此基礎上做工作量證明計算會帶來較高的能耗,同時降低系統(tǒng)的工作效率。研究者嘗試使用不同的共識算法來適應不同供應鏈場景的IoT-區(qū)塊鏈服務:Rejeb[11]使用權威證明(Proof of Authority, PoA)對IoT傳感器采集的用戶數(shù)據(jù)進行認證,PoA將記賬權授予最值得信賴的、高集成的主節(jié)點;Waltonchain[12]采用父子鏈架構的貢獻證明(Waltonchain Proof of Contribution, WPoC)保證IoT數(shù)據(jù)的信息透明,WPoC是一種混合共識機制,其父鏈采用PoW+PoS,子鏈則采用勞動證明(Proof of Labor),即“多勞多得”;Blockcloud[13]提出了服務證明(Proof of Service)來實現(xiàn)一個去中心化的物聯(lián)網(wǎng)服務框架;Gemini-chain[14]服務于加密貨幣交易監(jiān)管,在拜占庭容錯(Byzantine Fault Tolerance, BFT)共識機制的基礎上加入信用評級機制,據(jù)此調(diào)整節(jié)點權限;Hawk[15]、ProvChain[16]、Zcash[17]主要面向交易信息隱私保護問題,采用改進的輕量化PoS、PoW機制,在保證高安全性的同時兼顧改善了吞吐量和延遲問題。不難發(fā)現(xiàn),不同的共識算法適用于不同側重的供應鏈服務場景,在涉及供應鏈管理、自治的服務場景下,研究者較為看重節(jié)點在區(qū)塊鏈網(wǎng)絡中的信用、貢獻等屬性,但少有工作關注智能合約在供應鏈自治中的重要性。
為進一步探討供應鏈自治在與區(qū)塊鏈結合應用下的可能性,本文提出一種基于DPoS改進的共識機制,并在此基礎上提出了選舉供應鏈(Election-based Supply Chain, ESC)框架,該框架根據(jù)網(wǎng)絡節(jié)點在供應鏈中參與的智能合約活動計算其信用分,節(jié)點憑借信用分參與記賬人選舉,實現(xiàn)基于IoT-區(qū)塊鏈的供應鏈自治系統(tǒng)。
ESC中,智能合約是網(wǎng)絡節(jié)點間交互活動的主要載體。圖1顯示了ESC的一個簡單框架,它包括5種供應鏈基本角色類型:制造商、運輸商、零售商、消費者、IoT監(jiān)管部門。ESC通過代表選舉來保證各角色間形成自治,節(jié)點的競選依據(jù)是:根據(jù)其交互數(shù)據(jù)計算出的動態(tài)變化的信用分。當選為代表的節(jié)點獲得更高的權限,獲得一些額外的經(jīng)濟獎勵,并參與區(qū)塊鏈網(wǎng)絡的管理(數(shù)據(jù)打包、區(qū)塊生產(chǎn)等)。
圖1 ESC簡單框架
ESC中不同角色產(chǎn)生的數(shù)據(jù)被存儲在本地服務器中進行預處理,然后通過共識機制更新到區(qū)塊鏈上。圖2給出了一部分數(shù)據(jù)的類型。數(shù)據(jù)存儲通常包含三個步驟:
1)原始數(shù)據(jù)采集。IoT傳感器嚴格監(jiān)控供應鏈中的生產(chǎn)、運輸、倉儲等流程,它們自動收集產(chǎn)品在每一流程的相關參數(shù),并發(fā)送到本地服務器進行預處理。
2)數(shù)據(jù)預處理。因為遵循多種硬件/軟件協(xié)議,從多個IoT傳感器收集的原始數(shù)據(jù)的可讀性較差,預處理過程使這些原始數(shù)據(jù)易于訪問。
3)數(shù)據(jù)更新。通過有效的共識機制,預處理的數(shù)據(jù)被打包成一個新的區(qū)塊并更新到區(qū)塊鏈。
圖2 ESC數(shù)據(jù)存儲
智能合約提高了供應鏈角色的交互效率。在ESC中,智能合約的主要功能有:對于制造商,智能合約用于連接IoT傳感器并收集生產(chǎn)數(shù)據(jù),如果某些數(shù)據(jù)出現(xiàn)異常,智能合約可以及時報警并做出應急反應;對于運輸商,智能合約用于跟蹤運輸路線、監(jiān)測物流倉儲溫濕度等;對于零售商,智能合約用于與制造商指定采購合同、與消費者交易、處理售后服務等;對于消費者,智能合約用于與賣家簽訂購買協(xié)議、對產(chǎn)品進行評價、進行售后維權等;對于市場秩序監(jiān)管部門,智能合約是一些政策與建議,如提高稅率、改善生產(chǎn)要求等。
圖3 ESC節(jié)點類型及權限
表1 ESC關鍵參數(shù)描述
1.4.1 代表選舉
普通數(shù)據(jù)節(jié)點可注冊成為礦工。代表節(jié)點通過一個加權投票模型從所有礦工中選出,下面給出代表選舉模型。
定義1 代表選舉模型如下:
1.4.2 智能合約上鏈
圖4 ESC智能合約的鏈上更新過程
定義 2 智能合約的上鏈過程選舉模型如下:
對函數(shù)(10)求導,有:
圖5 函數(shù)
對函數(shù)(13)求導,得:
實驗結果的直方圖如圖6所示,其中:
圖6 對總費用范圍的影響
從圖6可以看出:
本文針對IoT-區(qū)塊鏈在供應鏈自治方面的應用中的共識機制改進問題,提出了選舉供應鏈(ESC)框架,它基于改進的DPoS共識機制,充分考慮了節(jié)點的活躍度與智能合約參與情況,并依此計算節(jié)點的信用分,根據(jù)信用分選舉代表并分配記賬權。ESC是一種面向供應鏈自治管理的解決方案,通過本文的定理證明得出,它對節(jié)點參與智能合約活動具有良好的激勵性;同時,仿真實驗結果表明,ESC能夠?qū)?jié)點自發(fā)的交易費行為起到較好的抑制作用。
智能合約在IoT-區(qū)塊鏈及其供應鏈應用中的積極作用越來越明顯,節(jié)點參與智能合約的編寫、測試、調(diào)用等工作,對維護整個系統(tǒng)的自治、自動化貢獻巨大。因此,下一步工作是研究智能合約解構、合約質(zhì)量評價、合約的自生成與監(jiān)管,進一步為構建供應鏈自治系統(tǒng)奠定基礎。
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Election-based supply chain: a supply chain autonomy framework based on blockchain
XU Yuntao1, ZHU Junwu1*, SUN Binwen1, SUN Maosheng2, CHEN Sihai3
(1,,225127,;2,,225127,;3,,224404,)
The combination of blockchain and supply chain is a popular research topic in recent years. The advantages of blockchain such as data traceability, tamper proof and distributed storage can guarantee good data security for supply chain, while the autonomy property of blockchain also provides possibility of supply chain autonomy. The autonomy of blockchain mainly depends on consensus mechanism, but the existing consensus mechanism is difficult to realize good support for supply chain autonomy. To solve the above problems, an election-based consensus mechanism based on Delegated Proof of Stake (DPoS) was proposed, and on this basis, a self-made framework of supply chain based on blockchain was constructed, namely Election-based Supply Chain (ESC). In ESC, the credit score of a node was first calculated according to the smart contract activities participated in by this node. Then, from the perspective of game theory, the influences of node active degree and credit score on stake under ESC were analyzed. Finally, theorem proving and simulation experiments verify that the proposed mechanism has a good incentive effect on nodes and can effectively inhibit the maximum transaction cost paid by rational nodes,and the inhibition increasing with the increase of the number of delegates.
supply chain; blockchain; smart contract; election; consensus algorithm; game theory
This work is partially supported by National Natural Science Foundation of China (61872313), Research Fund of Open Project of State Key Laboratory of Marine Engineering (1907), Jiangsu Water Conservancy Science and Technology Project (2017071), Key Research Project of Education Informatization in Jiangsu Province (20180012), Science and Technology Project of Emergency Management Department of Jiangsu Province (YJGL-YF-2021-3, YJGL-YF-2020-17), Yangzhou Science and Technology Program (YZ2019133, YZ2020174).
XU Yuntao, born in 1997, M. S. candidate. His research interests include blockchain, algorithmic game theory.
ZHU Junwu, born in 1972, Ph. D., professor. His research interests include artificial intelligence, knowledge engineering, algorithmic game theory.
SUN Binwen, born in 1999. His research interests include blockchain.
SUN Maosheng, born in 1971, Ph. D., senior engineer. His research interests include artificial intelligence.
CHEN Sihai, born in 1971, engineer. His research interests include Intelligent water affairs system integration, enterprise information applications.
TP311
A
1001-9081(2022)06-1770-06
10.11772/j.issn.1001-9081.2021091761
2021?10?13;
2022?01?11;
2022?01?13。
國家自然科學基金資助項目(61872313);海洋工程國家重點實驗室開放課題研究基金資助項目(1907);江蘇省水利科技項目(2017071);江蘇省教育信息化研究重點課題(20180012);江蘇省應急管理廳科技項目(YJGL-YF-2021-3, YJGL-YF-2020-17);揚州市科技計劃項目(YZ2019133, YZ2020174)。
許蘊韜(1997—),男,江蘇興化人,碩士研究生,CCF會員,主要研究方向:區(qū)塊鏈、算法博弈論;朱俊武(1972—),男,江蘇江都人,教授,博士生導師,博士,CCF高級會員,主要研究方向:人工智能、知識工程、算法博弈論;孫彬文(1999—),男,江蘇揚州人,主要研究方向:區(qū)塊鏈;孫茂圣(1971—),男,江蘇海安人,高級工程師,博士,主要研究方向:人工智能;陳四海(1971—),男,江蘇阜寧人,工程師,主要研究方向:智慧水務系統(tǒng)集成、企業(yè)信息化應用。