## 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
& Industry (5.0) & Industry (5.0) & SC (.0) & Smart device integration, disruption mitigation. & Real-time tracking of food & Resilient ledger structure. \\  & Transparency in donations to disaster zones. & Public DApp for donation campaign & EVM-compatible, smart contract, tractaking. & Campaign-level & Smart contract + digital & Donation trace from wallet & Immutable EVM-based logging. \\  & Medical relief SC during pandemics. & PLatform integrated blockchain. & IoT sensors, blockchain ledger. & Cold-chain distribution integrity. & Sensor validation and access policy. & End-to-end item flow. & Environmental + ledger validation. \\  & Disaster risk management and proportionalness. & Disaster risk coordination in disaster phases. & Smart contracts, decentralized consensus & Multi-agency coordination, data sharing, system scalability. & Decentralized access control, taxper- resistance. & Multi-agency coordination, data sharing, system scalability. & Immutable ledger of disaster operations. \\  & Lightweight disaster relief distribution & Blockchain + smartphones in ad hoc networks. & Smart process, PMN, phone-to-phone & Communication breakdown resilience. & Smart contract-based verification. & Physical package + contract mapping. & Immutable TX data. \\  & Decentralized humanitarian aid governance. & Ethereum- guaranteeing and routing. & Contracts, functionality,function even in the absence of infrastructure [158]. On the other hand, certain contributions remain at the conceptual level or provide limited technical depth. Systematic reviews and framework papers contribute to the literature from a theoretical perspective without implementing real systems [153]. Models lacking platform specification or concrete implementation often fall short in terms of technical soundness for security and data integrity [148; 149; 150]. Additionally, complex requirements, such as off-chain data integration, cold chain monitoring, or scenario-based donation routing, are either minimally addressed or entirely omitted in several works [152; 156]. Overall, blockchain-enabled supply chain applications exhibit significant potential in strengthening transparency, traceability, and data integrity in disaster responses. A hybrid architecture combining permissioned blockchain platforms (e.g., Hyperledger Fabric) with public systems (e.g., Ethereum, Polygon) may offer both scalability and operational security. #### 6.1.2 Refugee Logistics and Identity Management

Refugee logistics pose a dual challenge: ensuring access to humanitarian aid and enabling secure, verifiable identity management for displaced populations. Refugees often arrive in host countries without valid identification or having lost documents during the migration. Traditional centralized identity systems are ill-equipped to handle such scenarios, especially across borders. Blockchain technology has emerged as a transformative tool to address these limitations by enabling tamper-proof, decentralized identity verification mechanisms. Various approaches have been introduced to empower refugees through Self-sovereign identity (SSI) frameworks, digital certificates, and decentralized identity wallets. One implementation in Switzerland employed a blockchain-based SSI platform to enhance identification processes for Ukrainian refugees by eliminating paper dependency and enabling individuals to control their own identity data [160]. Another solution utilized Ethereum-based smart contracts to issue verifiable educational and employment certificates through immutable digital records [161]. Ensuring access to vital records, such as health, education, and identity documents, for refugees, especially children, has been recognized as a key challenge in displacement contexts. Blockchain-based systems have been proposed to address this gap by enabling the decentralized and tamper-proof storage of such documents, even in regions with limited infrastructure, thereby reducing the risk of long-term exclusion for vulnerable populations [162].