Table of Content

30 July 2022, Volume 40 Issue 4

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Blockchain

Architecture Design and Implementation of Seafood-Oriented Supply Chain Platform Based on Multiple Heterogeneous Blockchains

WU Ou, ZHANG He, WANG Yanze, LI Haoming, LI Shanshan

2022, 40(4):  539-554.  doi:10.3969/j.issn.0255-8297.2022.04.001

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Blockchain technology can be used to solve the problems of data fraud, low transparency and difficulty in tracking in traditional seafood supply chains. However, if organizations in a supply chain adopt a heterogeneous blockchain which is unable to exchange data and complement each other's functions, there will be value islands. To solve this problem, this paper chooses BitXHub cross-chain solution based on relay mechanism, then designs and implements a cross-border seafood supply chain platform that supports the interoperation of mainstream blockchain Hyperledger Fabric and Ethereum. Experimental results show that the system can process more than 937 transactions per second, which can meet the business requirements of actual scenes.

Evaluation Method of Blockchain Privacy Protection for Full Life Cycle of Transaction Data

ZHU Xuguang, XING Chunxiao, LI Wenqing, HAO Yingting

2022, 40(4):  555-566.  doi:10.3969/j.issn.0255-8297.2022.04.002

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This paper proposes an evaluation method of blockchain privacy protection for full life cycle of transaction data in view of the differences between blockchain and traditional information systems, analyzes blockchain privacy leakage risk and privacy protection methods from aspects of transaction data that are release, consensus, storage, and application to establish a blockchain privacy protection evaluation index system; conduct relative importance decision-making for index, and weight calculation using a dynamic index weight assignment method combining analytic hierarchy process and pairwise comparison; combine three dimensions of privacy protection strength, transaction data usability and privacy protection technical performance to calculate blockchain privacy protection related capability score. The analysis shows that the method enables a comprehensive evaluation of the level of blockchain privacy protection.

Distributed Notary Cross-Chain Model for Consortium Chain

YE Xianghe, LIU Xueye, WANG Binhui, XING Shusong

2022, 40(4):  567-582.  doi:10.3969/j.issn.0255-8297.2022.04.003

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Aiming at the problems of poor scalability, poor interoperability, and waste of storage resources in the consortium chain, a decentralized distributed notary cross-chain model is studied with the help of the original notary cross-chain mechanism. A node group is selected from each local chain as a distributed notary chain-global chain, and the global chain is used as a cross-chain medium to improve the degree of decentralization of the model. The JMeter tool is used to test the delay and throughput of the system, and theoretically from the perspective of system storage space utilization and security, the feasibility of the proposed cross-chain model is verified by using it in a medical and health scenario.

A Decentralized Storage Space Trading System under Blockchain Network

ZHANG Shuihai, SUN Haoyi, SUN Yiwei, PEI Bei, Lü Chunli

2022, 40(4):  583-599.  doi:10.3969/j.issn.0255-8297.2022.04.004

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In order to solve problems in centralized storage, a decentralized storage space transaction system is proposed based on the key technologies of blockchain, smart contract and lightning network. Three data encoding schemes are provided for fitting different orders, thus ensuring the security of user data, improving the space utilization of storage nodes and data recovery efficiency, and enhancing the adaptability to the complex environment of distributed storages. In addition, a "one day" rental delivery mechanism is designed based on under-the-chain micro-payment channel which is built through lightning networks, effectively relieving the pressure of data storage on the chain. Compared with previous distributed data sharing storage systems, the proposed system supports decentralization, short-term lease and multi-currency payment at the same time, and shows higher ability to meet the requirements of distributed storage space lease of the current era.

New Light Node Data Query Method for Medical Blockchains

ZHANG Xuewang, FU Kang, YE Caijin, WANG Kunlan

2022, 40(4):  600-610.  doi:10.3969/j.issn.0255-8297.2022.04.005

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In medical blockchain systems, users may be cheated by whole node when they request data from the whole node. Meanwhile, owing to the lack of storage, simple payment verification (SPV) and other verification methods of light node data are not applicable to medical blockchain systems. In order to solve these problems, this paper proposes a new light node data query method for medical blockchains. In the proposed method, the Merkle mountain range (MMR) with dynamic addition capability is introduced, and the latest valid block query algorithm based on recommendation trusted node selection and trusted node verification on sampling is designed. Accordingly, by using the commitment mechanism of the MMR and Merkle tree, the medical data sent by the whole node are verified by the user of the light node which holds the latest valid block obtained from a trusted node. Furthermore, the proposed method can be extended to the application of consortium blockchains. Analysis and experiments on the proposed method show that both time cost and space cost are in low overhead ranges.

Bloom Filter Optimization for Consortium Blockchain

WU Yihan, HUANG Jianhua, SHAO Xinghui, WANG Cheng

2022, 40(4):  611-622.  doi:10.3969/j.issn.0255-8297.2022.04.006

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Bloom filters are frequently used for read performance optimization of Hyperledger Fabric state database LevelDB, but they suffer from false positives, and LevelDB asks Bloom filters working in a uniform rather than adaptively adjusted configuration. In this paper, a unitized partial counting Bloom filter (PCBF) construction scheme is proposed by using a parallel element insertion and query computing mechanism, which combines double Hash and non-encrypted Hash to achieve fast insertion and query. Sorted string table (SSTable) priority is constructed based on open filter units and access times, while the filter units are adaptively adjusted by using a time-slice polling algorithm to achieve reasonable resource allocation. Experiments show that PCBF has a high insertion efficiency and can reduce the total number of false positives by about 20%, proving the feasibility of PCBF in high concurrency scenarios of permissioned blockchain.

An Efficient Query Method for Blockchain Traceability

LIU Wei, WANG Dong, SHE Wei, PAN Heng, SONG Xuan, TIAN Zhao

2022, 40(4):  623-638.  doi:10.3969/j.issn.0255-8297.2022.04.007

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In view of the low query efficiency of existing blockchain traceability systems, and the risk of data tampering coming up with the introduction of external databases, we proposes an efficient query method with blockchain-oriented traceability in this paper. First, by combining Bloom filter and Merkle tree, a BMerkle tree is proposed in order to form a new block structure. Under this block structure, the existence of transactions can be quickly retrieved, and the specific content of existing transactions can be found. Then, an optimized skip list structure hot_skiplist is proposed by adding an index outside the blockchain, realizing rapid block positioning, adjusting the index level dynamically based on the number of block accesses, and improving the query efficiency of frequently accessed blocks. Experiments show that this method can effectively improve the efficiency of traceability query under the condition of not tampering with blockchain data.

DPoS Consensus Algorithm Based on Node Weight

TIAN Zhihong, ZHAO Jindong, LI Shaokai, HOU Yanchen, HAN Shuangzhi, ZHAO Xiangfu

2022, 40(4):  639-652.  doi:10.3969/j.issn.0255-8297.2022.04.008

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Aiming at the problems of node attacks in the consensus mechanism of delegated proof of stake (DPoS) and the way to reduce the possibility of malicious nodes becoming representative nodes, an improved consensus algorithm, delegated proof of stake based on node weight (NW-DPoS) is proposed in this paper. NW-DPoS takes the advantages of IOTA consensus in security and stability and establishes trust relationships between nodes. Taking the node historical behavior information, weight value and online status as the factors to calculate recognition degree, NW-DPoS selects a node with high cumulative recognition degree as block producer. And according to the behavior of nodes, the nodes with malicious behavior are punished by reducing their cumulative recognitions. Simulation experiment and analysis show that NW-DPoS consensus algorithm can significantly reduce the probability of malicious nodes becoming representative nodes, and is more reliable than DPoS consensus mechanism in resisting double spend attack and bribery attack, thus improving the security of the system.

Anonymous and Traceable Data Trading Scheme Based on Blockchain

ZHU Ziqiang, YAO Zhongyuan, ZHU Weihua, ZHAO Haihong, PAN Changfeng, SI Xueming

2022, 40(4):  653-665.  doi:10.3969/j.issn.0255-8297.2022.04.009

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To solve the data leakages of user identity and other privacy data in the process of data trading in blockchain, a data asset trading scheme based on alliance chain and group signature is proposed. This paper adopts alliance chain node access mechanism to realize the identity authentication of registered users. A linkable group signature technology is introduced to realize user anonymity and traceability in the process of trading. Meanwhile, a fair data exchange strategy is implemented on the chain by using the smart contract. Finally, theoretical analysis and simulation results show that the scheme can achieve decentralized data trading with higher security and efficiency.

Dual Consensus Hybrid Blockchain Cross Heterogeneous Domain Identity Authentication Scheme

ZHANG Lihua, LIU Ji, CAO Yu, CHEN Shihong, ZHEN Chen, ZHANG Ganzhe

2022, 40(4):  666-680.  doi:10.3969/j.issn.0255-8297.2022.04.010

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Aiming at the serious loss of node performance in current blockchain-based identity authentication schemes, a cross heterogeneous domain identity authentication scheme based on double consensus hybrid chain is proposed. Multi-factor analysis method is used to optimize the Raft consensus algorithm based on comprehensive performance, realizing a reasonable evaluation of the comprehensive performance of nodes. System failures caused by poor performance of cross domain nodes are avoided by selecting nodes with excellent comprehensive performance as cross domain nodes. By working in combination with practical Byzantine fault tolerant (PBFT) consensus mechanism in supervisory nodes, the Byzantine fault tolerance of the authentication system is enhanced, and the problem of intra domain false authentication caused by malicious nodes is solved. In addition, SM9 broadcast cipher algorithm is used to encrypt communication data in the authentication process, so as to realize the two-way authentication and communication confidence of the system, and ensure the security of the system. Experiments show that the dual consensus authentication mechanism has better Byzantine fault tolerance and higher throughput than the single consensus authentication mechanism, and makes the system more secure and stable. Moreover, it reduces the calculation operation in single to single encryption and decryption, and saves calculation overhead and time overhead of the system.

Blockchain Consensus Mechanism for Risk Assessment Model of Heterogeneous Identity Alliance

YANG Yanbo, WAN Wunan, ZHANG Shibin, ZHANG Jinquan, QIN Zhi

2022, 40(4):  681-694.  doi:10.3969/j.issn.0255-8297.2022.04.011

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Existing heterogeneous identity alliance risk assessment systems are generally centralized, with single point of failure, internal mischief and loss of control of user data. Therefore, a blockchain-based risk assessment model for heterogeneous identity alliances is proposed. This model uses attribute encryption to ensure the secure storage of data and user control rights, and combines the idea of network fragmentation and aggregation signature technology, to propose a two-level consensus mechanism called grouped and aggregate-signature Byzantine fault tolerance (GABFT), which first groups network nodes using a consistent Hashing algorithm, and uses practical Byzantine fault tolerance (PBFT) improved by aggregated signatures within and between groups to reach consensus, then improves the processing efficiency of the proposed model, reduces the communication overhead, and supports dynamic changes of nodes. Finally, an experiment shows that compared to PBFT, GABFT reduces the number of communications required for nodes to reach consensus from squared to linear and improves the throughput by a factor of 2~3.

SlightDetection: A Static Analysis Tool for Smart Contracts Security Vulnerabilities on Ethereum

CHEN Xiaohan, ZHAO Xiangfu, ZHANG Dengji, FEI Jiajia

2022, 40(4):  695-712.  doi:10.3969/j.issn.0255-8297.2022.04.012

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Security vulnerabilities in Ethereum smart contracts may lead to immeasurable losses. To alleviate this problem, a smart contract vulnerability detection tool SlightDetection is proposed, which uses static program analysis technology to achieve full code coverage. The tool converts smart contract source codes into a corresponding abstract syntax tree, and translates it into an XML intermediate representation. Taking the characteristics of several classic vulnerabilities as an example, the tool writes a custom XPath rule library, and using the XML intermediate representation and the XPath library as inputs, the tool keeps traversing and matching the XPath rule base, till getting the report of vulnerability detection. This work tests 3 classic contracts, and fully demonstrates the faster and more accurate detection features of SlightDetection. The effectiveness of the tool is proved by testing a large number of smart contracts provided on Etherscan and manually verifying more than 100 of them.