Data lineage technology is a method of describing the relationships between data, which plays a crucial role in solving many challenges in the data marketplace, such as unauthorized data redistribution, data tampering, and false data transactions. However, the complexity of the multi-chain data marketplace, including factors such as data credibility, trust environment, data ownership, and relationship complexity, poses significant challenges to construct data lineages. To effectively address these challenges, we propose a data lineage construction method for multi-chain data marketplaces. This method mainly involves the following three steps: Firstly, map data assets to Data Non-Fungible Token (DataNFT) and use referable NFT (rNFT) to record data lineage. Secondly, when data assets require cross-chain transfer, the transfer message of DataNFT is broadcasted through the interchain NFT protocol, without the need for actual cross-chain transfer. Finally, we add weights to the data lineage link, enabling us to quickly locate problematic data based on weight sorting during data auditing. We have implemented a system prototype of this method and verified its effectiveness through experiments. The experimental results show that our proposed scheme not only ensures the correctness and completeness of data lineages, but also effectively reduces audit costs.

In blockchain-based data marketplaces, the cross-chain solution based on relay chains has become an effective way to support digital asset transfer between heterogeneous blockchains. If a digital asset is popular, it will be frequently transferred between multiple data marketplaces. Digital assets are typically represented as (Non-fungible Tokens) NFTs. However, when utilizing a cross-chain transfer scheme based on a relay chain that involves locking, unlocking and burning of the NFT, it can lead to significant transaction costs. Due to the frequent minting and burning of popular NFTs, they tend to consume a significant amount of gas, resulting in high transaction costs. To address this issue, we propose the DART scheme, a secure and low-cost cross-chain transaction scheme for popular digital assets based on (dynamic NFT) DNFT and relay chain. The scheme mainly includes three aspects: Firstly, the initial owner of (Data NFT) DataNFT locks it onto the gateway contract on SChain, mints a (Cross-chain NFT) CNFT on the relay chain that references the DataNFT for resale, and minted DataNFT on the destination blockchain until the CNFT is no longer being resold. Secondly, the DNFT standard is utilized to implement CNFTs. The DNFT standard records the transaction hash of each CNFT resale, ensuring the secure reselling of DataNFTs. Thirdly, the metadata of DataNFT is encrypted to ensure its security during cross-chain transmission. Finally, we selected Axelar Network as the relay network and successfully implemented a prototype of the system. The experimental results demonstrate the feasibility of our proposed scheme.

Nowadays, data are regarded as an intangible asset. In the data marketplace, data are treated as a commodity or service, data owners can gain economic revenue by selling their data ownership or data usage rights. However, the data marketplace is facing various threats and challenges, such as unauthorized data reselling, trade of bogus data, dishonest data ownership claims, and unreasonable revenue allocation. Particularly, in the process of data resale, the revenue allocation remains a challenge when the data are processed and resold in another format. To solve this problem, we propose a revenue allocation mechanism based on the referable Non-Fungible Token (rNFT) and Shapley value method. Firstly, we tokenize the data to NFT to ensure the data ownership is traceable; Secondly, we use rNFT to record the data lineage that ensures the data owner can participate in the revenue allocation when the data are resold; Finally, we calculate the contribution of each party by the Shapley value method to ensure fairness in revenue allocation. We implement a prototype of our scheme on Ethereum and evaluate it comprehensively. The test results indicate that our scheme can meet the performance requirements of the data marketplace and improve the revenue of data owners effectively.

In recent years, Vehicular Ad Hoc Network (VANET) has developed significantly. Coordination between vehicles can enhance driving safety and improve traffic efficiency. Due to the high dynamic characteristic of VANET, security has become one of the challenging problems. Trust of the message is a key element of security in VANET. This paper proposes a Manhattan Distance Based Trust Management model (MDBTM) in VANET environment which solves the problem in existing trust management research that considers the distance between the sending vehicle and event location. In this model, the Manhattan distance and the number of building obstacles are calculated by considering the movement relationship between the sending vehicle and event location. The Dijkstra algorithm is used to predict the path with the maximum probability, when the vehicle is driving toward the event location. The message scores are then calculated based on the Manhattan distance and the number of building obstacles. Finally, the scores are fused to determine whether to trust the message. The experimental results show that the proposed method has better performance than similar methods in terms of correct decision probability under different proportions of malicious vehicles, different numbers of vehicles, and different reference ranges.

The Internet of Things (IoT) is a large-scale complex network composed of a large number of heterogeneous devices, and due to the complexity of permission management in some scenarios of IoT, such as smart cities and smart healthcare, access control systems need to support strong flexibility. Permission delegation is an effective means to improve flexibility, but the delegated permission token in the current permission delegation scheme is a whole, and the recipient cannot re-delegate part of the permission in the received token. In this paper, a blockchain-based permission token segmentation scheme is proposed, which splits out part of the permissions in a permission token owned by the subject to generate a new token, so that the subject can control the fine-grained permissions in the token, enabling the subject to manage the permissions more flexibly. The permission combination scheme is then provided, and the permission invalidation problem in the token segmentation scheme is analyzed and discussed, and a token invalidation scheme is given. The security analysis shows that the scheme can reliably guarantee the security of authorized access.