Fig 1.
General Architecture Overview.
The SSI protocol involves Issuer, Holder, and Verifier roles interacting through web and mobile applications. Verifiable Credentials (VCs) are exchanged and managed over a data layer combining blockchain and decentralized storage. The network layer enables communication with the smart perception layer, which includes sensors and AI modules. An external silo represents an isolated data source interconnected with the system.
Table 1.
Blockchain-based solutions in the agricultural field.
Fig 2.
The figure illustrates a DAG-based ledger where each new transaction approves two previous tips. Confirmed transactions propagate from the genesis node, while tips represent unapproved transactions. The red node indicates a newly issued transaction awaiting confirmation over time.
Fig 3.
The Implementation environment of the Wheat Supply Chain.
The system integrates a Self-Sovereign Identity framework, web and mobile applications, a private IOTA-based blockchain network, off-chain storage using IPFS, and an AIoT layer combining AI modules and IoT sensors. A backend server coordinates interactions across these components to support secure data exchange within the supply chain.
Fig 4.
Analysis results with Mythril tool.
The figure presents the results obtained from analyzing the smart contract for potential vulnerabilities and security issues with the Mythril tool.
Fig 5.
The figure illustrates the dashboard of the Wasp node implemented on a Raspberry Pi board.
Fig 6.
The dashboard displays the Chain ID and the JSON-RPC URL, which are essential parameters for interacting with the blockchain network.
Fig 7.
Mobile application for credentials verification.
The figure shows the mobile app interface, including the authentication page and the verification page displaying authenticity checks and verification results.
Fig 8.
The interface displays the current status of the silo, including temperature, humidity, and weight. Users can check wheat quality using the provided button. The figure includes graphs showing temperature and humidity trends over time, a chart indicating used and total wheat quality, and a map indicating the location of the silo.
Fig 9.
Energy consumption Comparison: Ethereum vs IOTA.
The figure compares the energy consumption of the two blockchains for different transactions, including smart contract deployment and the execution of individual smart contract functions.
Fig 10.
Transactions costs Comparison in micro-ETH.
The figure illustrates a transaction cost comparison between the IOTA and Ethereum blockchains. The y-axis shows cost in micro-Ether (1 µETH = ). Costs for IOTA functions are converted to ETH-equivalent for comparison. Ethereum transactions are much more expensive, while IOTA costs are almost negligible.
Fig 11.
Throughput Comparison for the addFarmers() function.
The figure illustrates a throughput comparison between the IOTA and Ethereum blockchains. The y-axis shows the total number of transactions sent in each test (send rate), and the x-axis shows throughput as a percentage of successfully processed transactions. Each horizontal bar represents the performance of a blockchain at a given send rate.
Fig 12.
Evolution of the Number of PT in the addFarmers function.
The figure compares the number of permanent tips (PT) versus the total number of transactions for two tip selection algorithms: the standard WRW and the optimized AA-WRW in the addFramers function.
Fig 13.
Evolution of the Number of PT in the addTransportation Function.
The figure compares the number of permanent tips (PT) versus the total number of transactions for two tip selection algorithms: WRW and AA-WRW in the addTransportation function.