## 5 Blockchain-Based Supply Chain Security Solutions and Integration Models
### Data Privacy with Zero-Knowledge Proof (ZKP) and Confidential Transactions
#### 5.3.2 Architectural Model for Cross-Chain Supply Chains and Smart Contract Design
\begin{table}
\begin{tabular}{p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt}} \hline \hline
**Ref.** & **Application** & **Bockchain** & **Key** & **Security** & **Traceability** & **Data Integrity** & **Technical Challenges** \\ \hline \multirow{4}{*}{[170]} & Disaster relief & Ethereum-based donation & Smart contracts, ReactJS, Web3.0. & Immutable REactJS, transactions. & Real-time donation verification. & Ledger performance for audits. & Device inconsistency, limited to ETH, MetaMask dependency. \\  & Unified charity, CSR, crowdfundering. & Smart contract platform with anonymous ring signatures. & Ring signature, blockchain signatures. & Encrypted donor anonymity. & Campaign-level tracking. & Immutable cross-sector ledger. & Interoperability, data privacy, accessibility issues. \\  & NFT-based donation & NFT charity auction using FIFO Bocs. & Multi-sig, smart contracts, IPFS. & Verified NFT transactions. & Auction-based donation traceability. & Decentralized action for file storage. & High gas cost, auction process complexity. \\  & NFT and ID-based charity & Ethereum-based donation registry. & NFTs, registry. & decentralized ID, smart contracts. & Identity verification via DIDs. & NFT- campaign linkages. & Distributed control of donation. & System complexity, NFT market volatility. \\  & Blockchain + linearware for charities. & Charitable laware & Hybrid blockchain, insurance layer. & Fraud blockchain, insurance contract. & Public protection through insurance. & Smart contract-hardware for merkle Trees. & Node trust contract-based trust mechanism. & Node trust issues, lack of inspection tools. \\  & Cultural heritage donation tracking. & Provenance transactions. & Ethereum, donation logs. & Protection against misappropriation. & Transparent donation lineage. & Distributed donation proof. & Data storage and off-chain linkage limitations. \\  & Crypto-altruism overview. & Network of humanitarian aid. & Programmable blockchain notcasts. & Secure token exchange. & Funding flow visibility. & Long-term transparent records. & Trust cost, usability barriers. \\ \hline \hline \end{tabular}
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Table 14: Blockchain-based solutions for donation transparency platforms. was used to distribute digital food vouchers to Syrian refugees in Jordan. Through biometric authentication and blockchain wallets, beneficiaries were able to securely access aid while avoiding unnecessary intermediaries, reducing transaction fees and enhancing auditability [177; 179]. From a security perspective, blockchain eliminates manual errors and unauthorized access by ensuring role-based access control, tokenized credentials, and secure peer validation [179; 180]. For traceability, each unit of aid is tracked from donor input through logistics nodes to the end recipient, maintaining full visibility across the chain, especially with smart irrigation, PDS grain distribution, and sustainability-tagged food items [179; 181; 171; 182]. Regarding data integrity, immutable blockchain records enable the long-term verification of logistics actions and support needs-based planning, policy evaluation, and environmental compliance [177; 181]. These capabilities align with the goals of sustainable humanitarian logistics by combining transparency, accountability, and real-time coordination. Table 15 summarizes selected blockchain applications supporting food security and agriculture in humanitarian contexts, along with their corresponding strengths in enhancing security, traceability, and data integrity. ### Future Directions and Recommendations

Current research in blockchain-enabled supply chain security clearly demonstrates significant advantages in combating counterfeiting, ensuring data integrity, and enhancing traceability [48; 53; 54]. However, several challenges, security threats, and technical