When Humanitarian Work Meets Zero-Knowledge Technology
The Spanish Red Cross quietly made history in Barcelona this week. They’ve launched RedChain, a working aid-distribution system that runs on Ethereum’s public blockchain while keeping recipient identities completely private. Built with local partners BLOOCK and Billions Network, the platform already processed over 950,000 on-chain proofs during a year-long test run across Catalonia.
The problem they’re solving is one that’s plagued humanitarian organizations for years: donors want total transparency about where their money goes, but aid recipients need their privacy protected. RedChain uses zero-knowledge cryptography to deliver both. Donations become ERC-20 “digital aid credits” that can be traced all the way to the point of purchase, but the blockchain trail never reveals a name, address, or any personal detail.
Francisco López Romero, CTO of Creu Roja Catalunya, put it simply: “People seeking assistance shouldn’t have to choose between getting help and protecting their privacy.”
How the System Actually Works
RedChain splits sensitive information across three separate layers. The Red Cross’s internal case-management system handles the usual vetting process and keeps personal records off-chain, as it always has. Billions Network then issues a zero-knowledge credential that lives only in the beneficiary’s phone wallet—it can prove someone is eligible for aid without revealing why or who they are. BLOOCK’s infrastructure takes snapshots of every important event—a donation coming in, aid credits being minted, merchants redeeming them—and anchors those hashed records directly onto Ethereum’s mainnet.
The engineering team deliberately chose standard Solidity contracts to keep the system compatible with future blockchain developments. Beneficiaries use an Ionic-based mobile app that works on cheap Android phones. Digital signatures enforce strict role-based access, so Red Cross staff and merchants can only see what they need to see. Even if hackers broke into the Red Cross’s on-premise database, they’d only find hashed data that’s already publicly visible on the blockchain anyway.
The Technical Stack
• Public layer: Ethereum mainnet, ERC-20 smart contracts, on-chain proof anchoring
• Private layer: Creu Roja databases holding KYC details, spending receipts
• Identity layer: Billions Network zero-knowledge credentials in user wallets
• Interface layer: Ionic mobile app, QR-based merchant checkout, signature aggregation for gas efficiency
• Governance: multi-sig donor treasury, emergency pause switch held by an independent ethics committee
What This Means for Aid Organizations and the Crypto World
RedChain arrives at an interesting moment. Europe’s new MiCA regulations are demanding clearer distinctions between custodial and non-custodial digital assets, while the EU Data Act is tightening the screws on personal data handling. By anchoring proofs publicly but keeping identities in users’ own wallets, the Red Cross believes it satisfies GDPR’s data-minimization requirements while avoiding the embarrassing data breaches that have undermined earlier digitization efforts.
Other aid organizations are watching closely. The UN World Food Programme’s Building Blocks system uses a private Ethereum fork that stores hashed biometrics. Oxfam’s Sempo pilot in Vanuatu required phone-number verification. RedChain’s zero-knowledge approach leaves even fewer breadcrumbs, offering a template for privacy-conscious philanthropy on fully public blockchain infrastructure.
For crypto watchers, this is a utility story that doesn’t get enough attention: blockchains can support social-impact work without turning user data into a product. Gas costs remain a practical concern—the Red Cross currently batches proofs into daily Merkle roots to keep fees around €0.04 per transaction—but they’re already testing rollups to push that below €0.01.
Whether other NGOs adopt this model depends on how comfortable regulators get and whether donors embrace the approach. Early signs look promising. Several European charities are reportedly negotiating to license the technology, and Spanish tax authorities have hinted that cryptographic proofs might satisfy reporting requirements for tax-deductible donations.
If these trends continue, 2026 might be the year zero-knowledge technology finally escapes the DeFi labs and becomes standard infrastructure for public-interest work.
