## 6 Conclusions  
This paper introduced a detailed characterisation and data model for implementing traceability systems using smart contracts on Ethereum-compatible networks. By leveraging the Ethereum Virtual Machine (EVM), we benefit from a robust, flexible, and widely adopted platform for developing decentralised applications (dApps), ensuring security and immutability for traceability data. Two reference scenarios for data storage and notarisation were explored, namely storing cryptographic digests (i.e., hash keys) on-chain while keeping detailed data off-chain, and storing all traceability data fully on-chain. The first scenario significantly reduces storage costs and enhances privacy by minimising the amount of data stored on the blockchain. This approach also offers scalability benefits and maintains data integrity through hash keys, ensuring that any tampering with off-chain data can be detected. However, it relies on the availability and reliability of external storage solutions. In turn, the second scenario, although guaranteeing the immutability of all traceability data, incurs higher operational costs and faces challenges related to scalability and response times. The immutability and transparency provided by on-chain storage are valuable, but this later approach is less efficient and exposes potentially sensitive information to all network participants. Our analysis indicates that a balanced approach, combining off-chain and on-chain strategies, can provide a comprehensive and scalable solution for traceability systems. By optimising data storage and smart contract functionality, operational costs can be managed effectively while maintaining the desired levels of transparency, security, and privacy. In conclusion, blockchain technology, particularly through the use of smart contracts, offers a powerful tool for enhancing traceability in supply chains. Researchers and practitioners are encouraged to consider the trade-offs between on-chain and off-chain storage to develop systems that meet the specific requirements of their applications. Furthermore, the open nature of our proposal fosters collaboration and knowledge sharing among different industries. By establishing a set of best practices and fundamental principles, we enable organisations to learn from one another and adapt successful strategies across sectors. This cross-pollination of ideas can lead to more robust and effective traceability systems, ultimately benefiting consumers and enhancing trust in product authenticity and safety. In summary, while many existing blockchain traceability proposals focus on specific contexts, our sector-agnostic approach is designed to identify the essential elements of blockchain technology, making it relevant and applicable across a wide range of industries. This not only broadens the potential impact of our work but also positions it as a valuable resource for organisations looking to enhance their traceability efforts in an increasingly complex and interconnected marketplace. In addition, the proposed blockchain-based traceability framework can significantly enhance existing classical traceability systems by improving data integrity, automating verification processes, and fostering collaboration among supply chain partners. Through thoughtful integration strategies, the strengths of both classical and blockchain technologies can be leveraged, ultimately leading to more efficient and transparent supply chains. Future work will focus on further optimising these hybrid models and exploring their application in various industries to fully realise the potential of blockchain-enabled traceability systems. Conducting case studies across diverse sectors, such as pharmaceuticals, food, and textiles, would provide valuable insights into best practices and potential challenges, further informing the development of these systems.