## 3 The Critical Importance of Product Identity in Agricultural Supply Chains
### Economic Impact and ROI of Blockchain Traceability
The most significant novel contributions of the proposed framework lie in the integration of Decentralised Identifiers (DIDs), self-sovereign access control mechanisms, and smart contracts for automated certification validation. These components introduce new functionalities not yet fully explored or adopted in existing blockchain-based supply chain solutions. On the other hand, aspects such as regulatory data integration aligned with EBSI standards and the development of open interoperability frameworks remain conceptual at this stage, requiring further development and practical validation. From a practical perspective, the proposed framework offers multiple advantages for the agricultural supply chain sector. By providing a persistent product identity, it enhances authenticity assurance and mitigates risks of substitution and mislabelling fraud. The automation of certification verification through smart contracts reduces the manual workload for regulators and retailers, thereby improving operational efficiency. Additionally, the framework fosters greater consumer trust by offering transparent and verifiable product information, supporting claims such as organic production, fair trade certification, or PDO (Protected Designation of Origin) status. Nevertheless, its successful adoption will depend on overcoming scalability challenges, including the establishment of governance structures, onboarding of diverse stakeholders, and ensuring interoperability with existing platforms and national-level information systems. Figure 6 compares the proposed blockchain-based product identity framework against existing implementations by Walmart (IBM Food Trust), Carrefour (IBM Blockchain), and Provenance (Open Blockchain). The components assessed include product identity management, digital twins, immutable provenance, decentralised access control, smart contract validation, consumer interfaces, and regulatory integration. Colour coding distinguishes among confirmed practices (green), partially novel approaches (yellow), and novel contributions introduced by the proposed framework (red). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Criteria** & **Data** & **Real-Time** & **Verification** & **Scalability** & **Cost** & **Stakeholder Trust** \\ \hline \multirow{3}{*}{Traditional systems} & Low & Limited & High & Moderate & Lower & Variable \\  & – prone to opacity and & – often delayed & – manual audits & – centralised & – initial cost but & – trust depends \\  & opacity and & or manual & and paper & systems can & high long-term & on institutional \\  & silos & & records & bottleneck & inefficiency & reputation \\ \hline \multirow{3}{*}{Blockchain-based systems} & High & Enabled & Low & High & Higher & High \\  & – immutable & – supports & – cryptographic, & – scalable with & – initial cost but & – transparency \\  & and shared & automated IoT & automated & layer-2 or & better & builds \\  & ledger & inputs & verification & hybrid models & long-term ROI & verifiable trust \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparative analysis for blockchain solution with traditional systems.