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    2020 CCF China Blockchain Conference (CCF CBCC 2020)

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    Kubernetes-based Fabric chaincode management and high availability technology
    LIU Hongyu, LIANG Xiubo, WU Junhan
    Journal of Computer Applications    2021, 41 (4): 956-962.   DOI: 10.11772/j.issn.1001-9081.2020111977
    Abstract222)      PDF (1215KB)(420)       Save
    The core of the Blockchain as a Service(BaaS) platform is how to deploy the blockchain network on the cloud computing platform. Fabric deployment can be divided into static components and dynamic chaincodes according to the component startup time, and chaincode deployment is the core and the most complex part of Fabric cloudification. Because the Fabric has no interfaces for Kubernetes,the current solutions in the industry implement chaincode deployment through a series of auxiliary technologies, but these solutions do not incorporate the chaincodes into the Kubernetes management environment along with static components. In response to the existing problems of BaaS scheme, the following works were mainly done:1) a comprehensive study of the underlying infrastructure, especially of the Kubernetes platform with high availability in the production environment; 2) the cloud deployment of Kubernetes on Fabric was designed and implemented, especially in the chaincode part, a brand-new container control plug-in was used to realize the support for Kubernetes at the code level and complete the goal of incorporating chaincodes into Kubernetes environment management; 3) the functional computing service was used to manage the Fabric chaincodes to realize a brand-new chaincode execution mode, which means changing from the "start-wait-call-wait" mode to the "start-call-exit" mode. The above works in Fabric cloud deployment, especially in chaincode deployment management, have certain reference value for the optimization of the BaaS platform based on Fabric and Kubernetes.
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    Formal verification of smart contract for access control in IoT applications
    BAO Yulong, ZHU Xueyang, ZHANG Wenhui, SUN Pengfei, ZHAO Yingqi
    Journal of Computer Applications    2021, 41 (4): 930-938.   DOI: 10.11772/j.issn.1001-9081.2020111732
    Abstract204)      PDF (1289KB)(785)       Save
    The advancement of network technologies such as bluetooth and WiFi has promoted the development of the Internet of Things(IoT). IoT facilitates people's lives, but there are also serious security issues in it. Without secure access control, illegal access of IoT may bring losses to users in many aspects. Traditional access control methods usually rely on a trusted central node, which is not suitable for an IoT environment with nodes distributed. The blockchain technology and smart contracts provide a more effective solution for access control in IoT applications. However, it is difficult to ensure the correctness of smart contracts used for access control in IoT applications by using general test methods. To solve this problem, a method was proposed to formally verify the correctness of smart contracts for access control by using model checking tool Verds. In the method, the state transition system was used to define the semantics of the Solidity smart contract, the Computation Tree Logic(CTL) formula was used to describe the properties to be verified, and the smart contract interaction and user behavior were modelled to form the input model of Verds and the properties to be verified. And then Verds was used to verify whether the properties to be verified are correct. The core of this method is the translation from a subset of Solidity to the input model of Verds. Experimental results on two smart contracts for access control of IoT source show that the proposed method can be used to verify some typical scenarios and expected properties of access control contracts, thereby improving the reliability of smart contracts.
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    Data sharing model of smart grid based on double consortium blockchains
    ZHANG Lihua, WANG Xinyi, HU Fangzhou, HUANG Yang, BAI Jiayi
    Journal of Computer Applications    2021, 41 (4): 963-969.   DOI: 10.11772/j.issn.1001-9081.2020111721
    Abstract294)      PDF (1411KB)(763)       Save
    Considering the data sharing difficulties and the risk of privacy disclosure in grid cloud server based on blockchain, a Data Sharing model based on Double Consortium Blockchains in smart grid(DSDCB) was proposed. Firstly, the data of electricity was stored under-chain by Inter Planetary File System(IPFS), the IPFS file fingerprints were stored on-chain, and the electricity data was shared to other consortium blockchain based on the multi-signature notary technology. Secondly, with ensuring privacy from leakage, proxy re-encryption and secure multi-party computing were combined to share single-node or multi-node security data. Finally, fully homomorphic encryption algorithm was used to integrate ciphertext data reasonably without decrypting the electricity data. The 51% attack, sybil attack, replay attack and man-in-the-middle attacks were resisted by the single-node cross-chain data sharing model of DSDCB. It was verified that the security and privacy of data were guaranteed by the secure multi-party cross-chain data sharing model of DSDCB when the number of malicious participants was less than k and the number of honest participants was more than 1. The simulation comparison shows that the computational cost of the DSDCB model is lower than those of Proxy Broadcast Re-Encryption(PBRE) and Data Sharing scheme based on Conditional PBRE(CPBRE-DS), and the model is more feasible than the Fully Homomorphic Non-interactive Verifiable Secret Sharing(FHNVSS) scheme.
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    Overview of blockchain consensus mechanism for internet of things
    TIAN Zhihong, ZHAO Jindong
    Journal of Computer Applications    2021, 41 (4): 917-929.   DOI: 10.11772/j.issn.1001-9081.2020111722
    Abstract940)      PDF (1143KB)(1659)       Save
    With the continuous development of digital currency, the blockchain technology has attracted more and more attention, and the research on its key technology, consensus mechanism, is particularly important. The application of blockchain technology in the Internet of Things(IoT) is one of the hot issues. Consensus mechanism is one of the core technologies of blockchain, which has an important impact on IoT in terms of decentralization degree, transaction processing speed, transaction confirmation delay, security, and scalability.Firstly, the architecture characteristics of IoT and the lightweight problem caused by resource limitation were described, the problems faced in the implementation of the blockchain in IoT were briefly summarized, and the demands of blockchain in IoT were analyzed by combining the operation flow of bitcoin. Secondly, the consensus mechanisms were divided into proof class, Byzantine class and Directed Acyclic Graph(DAG) class, and the working principles of these various classes of consensus mechanisms were studied, their adaptabilities to IoT were analyzed in terms of communication complexity, their advantages and disadvantages were summarized, and the combination architectures of the existing consensus mechanisms and IoT were investigated and analyzed. Finally, the problems of IoT, such as high operating cost, poor scalability and security risks were deeply studied, the analysis results show that the Internet of Things Application(IOTA) and Byteball consensus mechanisms based on DAG technology have the advantages of fast transaction processing speed, good scalability and strong security in the case of having a large number of transactions, and they are the development directions of blockchain consensus mechanism in the field of IoT in the future.
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    Data trading scheme based on blockchain and trusted computing
    ZHANG Xuewang, YIN Zijie, FENG Jiaqi, YE Caijin, FU Kang
    Journal of Computer Applications    2021, 41 (4): 939-944.   DOI: 10.11772/j.issn.1001-9081.2020111723
    Abstract460)      PDF (1137KB)(1042)       Save
    Aiming at the problem of data being easily copied and the realization of data confidentiality in current data trading process, a data trading scheme based on blockchain and trusted computing was proposed. First, the blockchain was applied to record data information, trading information and data usage records, which facilitated to confirm the rights of data assets and data provenance. Then, the trusted computing and encryption algorithms were used to ensure the security of the trading data transmission. Finally, the algorithms provided by the data owners and demanders were applied to complete the calculation in the trusted computing environment, after that, the results were output and encrypted to return to the demanders. In the proposed scheme, the demanders can use the data for calculation without revealing data from the data subjects, and the transmission security is guaranteed through trusted encryption.
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    Digital music copyright management system based on blockchain
    ZHANG Guochao, TANG Huayun, CHEN Jianhai, SHEN Rui, HE Qinming, HUANG Butian
    Journal of Computer Applications    2021, 41 (4): 945-955.   DOI: 10.11772/j.issn.1001-9081.2020111731
    Abstract509)      PDF (2086KB)(1027)       Save
    It is of great significance to apply the blockchain technology to the field of digital music copyright management in view of the difficulties in copyright confirmation, infringement monitoring, right protection and evidence collection, royalty settlement and other problems in the traditional music copyright industry. A digital music copyright management system was designed and constructed by using the VNT Chain blockchain platform. In the system, the blockchain technology was used to provide the proof of music copyright and realize the evidence solidification, the Shazam algorithm was used to provide the proof of originality for music copyright, and the smart contract was used to guarantee the security and reliability of transactions. This system included six function modules:user management, copyright registration, copyright trading, infringement monitoring, evidence solidification and music ecology, covering the main parts of copyright management. According to different needs of business data, blockchain, InterPlanetary File System(IPFS) and MySQL were adopted as storage engines respectively for the system. Experimental results show that the copyright registration time of each music increases by about 1.9 s, and the storage of music feature fingerprint data of one song on IPFS costs about 8 MB averagely, which meets the expected system performance requirements.
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2022 Vol.42 No.11

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Honorary Editor-in-Chief: ZHANG Jingzhong
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