The Spanish Red Cross has introduced RedChain, a blockchain-based aid distribution platform designed to offer auditable transparency for donors while preserving the privacy of recipients, using cryptographic proofs and zero-knowledge credential technology.
The Spanish Red Cross (Creu Roja) has deployed RedChain, a digital system that tracks the entire lifecycle of humanitarian aid — from donation to disbursement — on a public blockchain, providing real-time transparency into funds without exposing sensitive recipient information. The platform was developed in collaboration with Barcelona-based infrastructure provider BLOOCK and zero-knowledge credential firm Billions Network.
Instead of paper vouchers or prepaid cards, RedChain issues ERC-20 aid credits on the Ethereum blockchain that beneficiaries receive in a mobile wallet and can spend at participating merchants using QR codes. Personal data, such as names, contact details and case records, is stored off-chain in the Red Cross’s own systems, while the public blockchain is used solely as a verification layer using hashes, timestamps and integrity proofs.
Donors and administrators can audit aggregated, verifiable information about when and where funds are allocated and spent, but the system is intentionally designed so that no party can reconstruct individual identities from on-chain records. A representative of Creu Roja explained that RedChain was “explicitly designed so that transparency applies to flows and outcomes, not individuals”, ensuring accountability without compromising the privacy and dignity of aid recipients.
Transparent aid flows without exposing personal data
The Spanish Red Cross frames the initiative as a response to growing pressure from humanitarian donors who want assurance that aid reaches its intended purpose without turning vulnerable communities into data sources. As Francisco López Romero, CTO of Creu Roja Catalunya, put it, “people seeking assistance shouldn’t have to choose between getting help and protecting their privacy”.
Recipients receive digital credits directly on their phones, allowing them to spend them at authorized point-of-sale locations in a manner indistinguishable from regular purchases, thus removing any visible markers of humanitarian aid and avoiding stigmatization.
From a technical perspective, the system uses a hybrid trust model: ERC-20 tokens represent allocated aid, while spending records and eligibility checks remain off-chain, linked to cryptographic proofs recorded on the blockchain. BLOOCK describes its role as operating the blockchain as a “certification layer”, where any modification of internal records would fail verification against the immutable on-chain proofs.
Meanwhile, Billions Network provides the zero-knowledge credential layer, enabling beneficiaries to prove eligibility without disclosing personal attributes. Proofs are held in the user’s wallet instead of a centralized identity registry.
