許蘊(yùn)韜,朱俊武*,孫彬文,孫茂圣,陳四海
選舉供應(yīng)鏈:基于區(qū)塊鏈的供應(yīng)鏈自治框架
許蘊(yùn)韜1,朱俊武1*,孫彬文1,孫茂圣2,陳四海3
(1.揚(yáng)州大學(xué) 信息工程學(xué)院,江蘇 揚(yáng)州 225127; 2.揚(yáng)州大學(xué) 信息化建設(shè)與管理處,江蘇 揚(yáng)州 225127; 3.阜寧縣自來(lái)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(yīng)鏈的結(jié)合應(yīng)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(chǔ)等優(yōu)點(diǎn)可以為供應(yīng)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(yīng)鏈自治提供了可能。區(qū)塊鏈的自治主要依賴于共識(shí)機(jī)制,然而現(xiàn)有共識(shí)機(jī)制難以實(shí)現(xiàn)對(duì)供應(yīng)鏈自治的良好支持。針對(duì)上述問(wèn)題,提出一種基于委托權(quán)益證明(DPoS)的選舉型共識(shí)機(jī)制,并在此基礎(chǔ)上構(gòu)建了一個(gè)基于區(qū)塊鏈的供應(yīng)鏈自制框架:選舉供應(yīng)鏈(ESC)。在ESC中,先根據(jù)節(jié)點(diǎn)參與的智能合約活動(dòng)計(jì)算其信用分,然后從博弈論的角度分析ESC下節(jié)點(diǎn)的活躍度和信用分?jǐn)?shù)對(duì)其權(quán)益的影響。最后,通過(guò)定理證明與仿真實(shí)驗(yàn)驗(yàn)證了該機(jī)制對(duì)節(jié)點(diǎn)具有良好的激勵(lì)作用,能有效抑制理性節(jié)點(diǎn)支付的最大交易費(fèi)用,且抑制的力度會(huì)隨著代表數(shù)量的增加而增大。
供應(yīng)鏈;區(qū)塊鏈;智能合約;選舉;共識(shí)算法;博弈論
傳統(tǒng)供應(yīng)鏈在數(shù)據(jù)溯源、數(shù)據(jù)安全性、數(shù)據(jù)存儲(chǔ)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(chǔ)等優(yōu)點(diǎn),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(qiáng)的自治屬性,這為供應(yīng)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(yīng)鏈的自動(dòng)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(jiǎn)單的比特幣交易。近年來(lái),隨著以太坊、Hyperledger Fabric等內(nèi)置圖靈完備開(kāi)發(fā)環(huán)境的區(qū)塊鏈平臺(tái)的發(fā)布,智能合約的計(jì)算功能得到進(jìn)一步完善。在區(qū)塊鏈與物聯(lián)網(wǎng)(Internet of Things, IoT)等技術(shù)的加持下,傳統(tǒng)供應(yīng)鏈中的生產(chǎn)、裝配、運(yùn)輸、倉(cāng)儲(chǔ)等流程均可利用智能合約實(shí)現(xiàn)不同程度的自動(dòng)化。
近幾年工業(yè)界十分重視IoT-區(qū)塊鏈在供應(yīng)鏈中的應(yīng)用。文獻(xiàn)[6]中綜述了區(qū)塊鏈在供應(yīng)鏈管理中的應(yīng)用,分析了不同行業(yè)下供應(yīng)鏈的需求特點(diǎn)與相應(yīng)的區(qū)塊鏈解決方案;文獻(xiàn)[7]中對(duì)IoT-區(qū)塊鏈系統(tǒng)網(wǎng)絡(luò)進(jìn)行了詳盡的調(diào)查分析,列舉并對(duì)比了現(xiàn)有IoT-區(qū)塊鏈系統(tǒng)采用的各種共識(shí)機(jī)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(shí)機(jī)制,但由于IoT設(shè)備的計(jì)算和存儲(chǔ)能力有限,在此基礎(chǔ)上做工作量證明計(jì)算會(huì)帶來(lái)較高的能耗,同時(shí)降低系統(tǒng)的工作效率。研究者嘗試使用不同的共識(shí)算法來(lái)適應(yīng)不同供應(yīng)鏈場(chǎng)景的IoT-區(qū)塊鏈服務(wù):Rejeb[11]使用權(quán)威證明(Proof of Authority, PoA)對(duì)IoT傳感器采集的用戶數(shù)據(jù)進(jìn)行認(rèn)證,PoA將記賬權(quán)授予最值得信賴的、高集成的主節(jié)點(diǎn);Waltonchain[12]采用父子鏈架構(gòu)的貢獻(xiàn)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(shí)機(jī)制,其父鏈采用PoW+PoS,子鏈則采用勞動(dòng)證明(Proof of Labor),即“多勞多得”;Blockcloud[13]提出了服務(wù)證明(Proof of Service)來(lái)實(shí)現(xiàn)一個(gè)去中心化的物聯(lián)網(wǎng)服務(wù)框架;Gemini-chain[14]服務(wù)于加密貨幣交易監(jiān)管,在拜占庭容錯(cuò)(Byzantine Fault Tolerance, BFT)共識(shí)機(jī)制的基礎(chǔ)上加入信用評(píng)級(jí)機(jī)制,據(jù)此調(diào)整節(jié)點(diǎn)權(quán)限;Hawk[15]、ProvChain[16]、Zcash[17]主要面向交易信息隱私保護(hù)問(wèn)題,采用改進(jìn)的輕量化PoS、PoW機(jī)制,在保證高安全性的同時(shí)兼顧改善了吞吐量和延遲問(wèn)題。不難發(fā)現(xiàn),不同的共識(shí)算法適用于不同側(cè)重的供應(yīng)鏈服務(wù)場(chǎng)景,在涉及供應(yīng)鏈管理、自治的服務(wù)場(chǎng)景下,研究者較為看重節(jié)點(diǎn)在區(qū)塊鏈網(wǎng)絡(luò)中的信用、貢獻(xiàn)等屬性,但少有工作關(guān)注智能合約在供應(yīng)鏈自治中的重要性。
為進(jìn)一步探討供應(yīng)鏈自治在與區(qū)塊鏈結(jié)合應(yīng)用下的可能性,本文提出一種基于DPoS改進(jìn)的共識(shí)機(jī)制,并在此基礎(chǔ)上提出了選舉供應(yīng)鏈(Election-based Supply Chain, ESC)框架,該框架根據(jù)網(wǎng)絡(luò)節(jié)點(diǎn)在供應(yīng)鏈中參與的智能合約活動(dòng)計(jì)算其信用分,節(jié)點(diǎn)憑借信用分參與記賬人選舉,實(shí)現(xiàn)基于IoT-區(qū)塊鏈的供應(yīng)鏈自治系統(tǒng)。
ESC中,智能合約是網(wǎng)絡(luò)節(jié)點(diǎn)間交互活動(dòng)的主要載體。圖1顯示了ESC的一個(gè)簡(jiǎn)單框架,它包括5種供應(yīng)鏈基本角色類型:制造商、運(yùn)輸商、零售商、消費(fèi)者、IoT監(jiān)管部門。ESC通過(guò)代表選舉來(lái)保證各角色間形成自治,節(jié)點(diǎn)的競(jìng)選依據(jù)是:根據(jù)其交互數(shù)據(jù)計(jì)算出的動(dòng)態(tài)變化的信用分。當(dāng)選為代表的節(jié)點(diǎn)獲得更高的權(quán)限,獲得一些額外的經(jīng)濟(jì)獎(jiǎng)勵(lì),并參與區(qū)塊鏈網(wǎng)絡(luò)的管理(數(shù)據(jù)打包、區(qū)塊生產(chǎn)等)。
圖1 ESC簡(jiǎn)單框架
ESC中不同角色產(chǎn)生的數(shù)據(jù)被存儲(chǔ)在本地服務(wù)器中進(jìn)行預(yù)處理,然后通過(guò)共識(shí)機(jī)制更新到區(qū)塊鏈上。圖2給出了一部分?jǐn)?shù)據(jù)的類型。數(shù)據(jù)存儲(chǔ)通常包含三個(gè)步驟:
1)原始數(shù)據(jù)采集。IoT傳感器嚴(yán)格監(jiān)控供應(yīng)鏈中的生產(chǎn)、運(yùn)輸、倉(cāng)儲(chǔ)等流程,它們自動(dòng)收集產(chǎn)品在每一流程的相關(guān)參數(shù),并發(fā)送到本地服務(wù)器進(jìn)行預(yù)處理。
2)數(shù)據(jù)預(yù)處理。因?yàn)樽裱喾N硬件/軟件協(xié)議,從多個(gè)IoT傳感器收集的原始數(shù)據(jù)的可讀性較差,預(yù)處理過(guò)程使這些原始數(shù)據(jù)易于訪問(wèn)。
3)數(shù)據(jù)更新。通過(guò)有效的共識(shí)機(jī)制,預(yù)處理的數(shù)據(jù)被打包成一個(gè)新的區(qū)塊并更新到區(qū)塊鏈。
圖2 ESC數(shù)據(jù)存儲(chǔ)
智能合約提高了供應(yīng)鏈角色的交互效率。在ESC中,智能合約的主要功能有:對(duì)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(shí)報(bào)警并做出應(yīng)急反應(yīng);對(duì)于運(yùn)輸商,智能合約用于跟蹤運(yùn)輸路線、監(jiān)測(cè)物流倉(cāng)儲(chǔ)溫濕度等;對(duì)于零售商,智能合約用于與制造商指定采購(gòu)合同、與消費(fèi)者交易、處理售后服務(wù)等;對(duì)于消費(fèi)者,智能合約用于與賣家簽訂購(gòu)買協(xié)議、對(duì)產(chǎn)品進(jìn)行評(píng)價(jià)、進(jìn)行售后維權(quán)等;對(duì)于市場(chǎng)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(diǎn)類型及權(quán)限
表1 ESC關(guān)鍵參數(shù)描述
1.4.1 代表選舉
普通數(shù)據(jù)節(jié)點(diǎn)可注冊(cè)成為礦工。代表節(jié)點(diǎn)通過(guò)一個(gè)加權(quán)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(guò)程
定義 2 智能合約的上鏈過(guò)程選舉模型如下:
對(duì)函數(shù)(10)求導(dǎo),有:
圖5 函數(shù)
對(duì)函數(shù)(13)求導(dǎo),得:
實(shí)驗(yàn)結(jié)果的直方圖如圖6所示,其中:
圖6 對(duì)總費(fèi)用范圍的影響
從圖6可以看出:
本文針對(duì)IoT-區(qū)塊鏈在供應(yīng)鏈自治方面的應(yīng)用中的共識(shí)機(jī)制改進(jìn)問(wèn)題,提出了選舉供應(yīng)鏈(ESC)框架,它基于改進(jìn)的DPoS共識(shí)機(jī)制,充分考慮了節(jié)點(diǎn)的活躍度與智能合約參與情況,并依此計(jì)算節(jié)點(diǎn)的信用分,根據(jù)信用分選舉代表并分配記賬權(quán)。ESC是一種面向供應(yīng)鏈自治管理的解決方案,通過(guò)本文的定理證明得出,它對(duì)節(jié)點(diǎn)參與智能合約活動(dòng)具有良好的激勵(lì)性;同時(shí),仿真實(shí)驗(yàn)結(jié)果表明,ESC能夠?qū)?jié)點(diǎn)自發(fā)的交易費(fèi)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(yīng)鏈應(yīng)用中的積極作用越來(lái)越明顯,節(jié)點(diǎn)參與智能合約的編寫、測(cè)試、調(diào)用等工作,對(duì)維護(hù)整個(gè)系統(tǒng)的自治、自動(dòng)化貢獻(xiàn)巨大。因此,下一步工作是研究智能合約解構(gòu)、合約質(zhì)量評(píng)價(jià)、合約的自生成與監(jiān)管,進(jìn)一步為構(gòu)建供應(yīng)鏈自治系統(tǒng)奠定基礎(chǔ)。
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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
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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(guó)家自然科學(xué)基金資助項(xiàng)目(61872313);海洋工程國(guó)家重點(diǎn)實(shí)驗(yàn)室開(kāi)放課題研究基金資助項(xiàng)目(1907);江蘇省水利科技項(xiàng)目(2017071);江蘇省教育信息化研究重點(diǎn)課題(20180012);江蘇省應(yīng)急管理廳科技項(xiàng)目(YJGL-YF-2021-3, YJGL-YF-2020-17);揚(yáng)州市科技計(jì)劃項(xiàng)目(YZ2019133, YZ2020174)。
許蘊(yùn)韜(1997—),男,江蘇興化人,碩士研究生,CCF會(huì)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(dǎo)師,博士,CCF高級(jí)會(huì)員,主要研究方向:人工智能、知識(shí)工程、算法博弈論;孫彬文(1999—),男,江蘇揚(yáng)州人,主要研究方向:區(qū)塊鏈;孫茂圣(1971—),男,江蘇海安人,高級(jí)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(wù)系統(tǒng)集成、企業(yè)信息化應(yīng)用。