Blockchain systems have received increased interest over the past few years, and several new fields of use, such as supply chain systems, are being investigated. Since blockchain is still a new technology, various papers have explored how to apply it to support use cases outside the limited scope of digital currencies. Systems require solid technological implementation and perceived trust among users to ensure their interests and successful usage in practice. This study aimed to understand what graphic user interface (GUI) elements of a blockchain-based system make users trust that their best interests, such as security and privacy, are maintained in the systems. As a case study, we developed a few blockchain-based supply chain GUI mockups with different elements that reflect the security and privacy features of the system. We then conducted 30 interviews in Norway and China to collect the users’ opinions on whether the information presented in the GUIs helps them trust the system. The results show that users want access to as much information and data as the system can provide. The users’ trust in the system increases if the GUI features give users the impression that the inner workings of the blockchain-based system are transparent. However, users prefer the information presented as more conceptual than technical in the first place. However, users appreciate the possibility of clicking on the conceptual explanation and getting more in-depth blockchain-related technical information if needed.

Traceability systems are important for solving problems due to the increasing scale of the global supply chain, such as food safety crises and market disorder. Blockchain, as an immutable and decentralized ledger, is able to optimize the traditional traceability system by ensuring the transparency and reliability of the system data. However, the use of blockchain technology may lead to a rapid increase in the complexity of system design and development. It is challenging to address widespread and complicated business, changeable processes, and massive data in practice, which are the main factors restricting the wide application of a blockchain-based traceability system (BTS). Therefore, in this paper, we reviewed relevant studies and proposed a reference architecture for BTSs. The proposed reference architecture can improve the cohesiveness, maintainability, and extensibility of BTSs through domain-driven design (DDD) and microservices. Considering the efficiency reduction caused by massive data and complicated data structure, we further changed the traditional single blockchain framework into multiple subchain networks, which could improve development efficiency and system performance. With the guidance of the architecture trade-off analysis method (ATAM), we evaluated our reference architecture and implemented a prototype in the salmon supply chain scenario. The results show that our solution is effective and adaptable to meet the requirements of BTSs.