# A Blockchain and IoT-Enabled Framework for Ethical and Secure Coffee Supply Chains
## 5 Challenges and Future Work  
While the proposed framework and results demonstrate the potential and novelty of this research, a number of challenges were encountered that define its current limitations and can provide a guide for future development. One primary challenge was the use of simulated IoT sensor data rather than physical device integration. Although structured datasets were used to emulate realistic sensor outputs, these do not completely reflect real-world device behavior, potential sensor failures, or recurrent connectivity issues. We acknowledge that the absence of live sensor deployment limits the current system's reproducibility and hardware-specific insights. As part of future work, our framework will be extended to incorporate IoT hardware using platforms such as Raspberry Pi and Node-RED to allow for live data collection and on-chain validation [56]. Another challenge was the variability in transaction execution time, which ranged from 12 to 108 s during testing on the Sepolia testnet via Remix IDE and Metamask. These delays were influenced by external infrastructure factors which were beyond the smart contract's control. Our future work will include deploying the smart contract in a more stable or performance-optimized blockchain environment such as a private Ethereum network in order to achieve more consistent responsiveness, especially in preparation for IoT-triggered events in the supply chain process. Our future work will also include a \begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**STRIDE Category** & **Potential Threat in the System** & **Mitigation Strategy (Current and Planned)** \\ \hline
**Spoofing Identity** & Malicious actors may impersonate legitimate users or sensors to submit falsified data. & Smart contracts enforce strict user registration via _registeristers_ and access control using _onlyOwner_. Sensor authentication protocols are part of future enhancements. \\ \hline
**Tampering with Data** & Attackers could alter sensor data during transmission or before it is stored on-chain. & Blockchain immutability ensures post-submission integrity. Future work includes encrypted sensor transmission and data signing. \\ \hline
**Repudiation** & Users might deny initiating or participating in transactions. & Ethereum stores all transactions on-chain with cryptographic signatures and timestamps, enabling full audit trails. \\ \hline
**Information Disclosure** & Leakage of sensitive data like GPS location or user identity. & Minimal Personally Identifiable Information is recorded. Future work includes off-chain encrypted storage and proxy encryption mechanisms. \\ \hline
**Denial of Service (DoS)** & Excessive requests may overload sensors or smart contracts. & Ethereum’s gas mechanism limits resource abuse. Rate limiting and transaction prioritization are proposed for future deployment. \\ \hline
**Elevation of Privivi-lege** & Unauthorized users might access restricted contract functions. & Solidity-based role enforcement using _onlyOwner_ ensures role-based restrictions. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: STRIDE threat modeling for the proposed blockchain–IoT framework. comprehensive security assessment, including threat modeling of common supply chain attacks such as data spoofing, unauthorized access, and sensor tampering, in order to evaluate the robustness of the proposed blockchain-IoT integration. While this study emphasizes functional and architectural validation, we recognize the need for formal modeling of system parameters such as latency, reliability, and throughput. Future work will include mathematical modeling and simulation-driven optimization after real-world IoT data are integrated into the framework, in addition to comparison with other platforms such as Hyperledger [57]. Future work will also explore interoperability with existing supply chain certification platforms such as Rainforest Alliance and Fairtrade [58] by aligning our transaction schema with standardized data formats such as GS1 EPCIS 2.0 [59].