Blockchain demo
Cold-Chain Provenance
A vaccine shipment passes through four organizations: manufacturer, carrier, distributor, pharmacy. None of them should be able to rewrite what happened on the way. This demo runs that shipment on a consortium blockchain built in your browser, with ECDSA-signed custody events, Merkle roots, and proof-of-authority sealing. Then play the bad actor. Cover up a temperature breach or forge another company's inspection, and watch the ledger catch both.
BioNova Labs
Manufacturer · Basel
🔑 key pending…
ArcticFreight
Cold-chain carrier · Basel → Newark
🔑 key pending…
MedSupply DC
Distributor · Newark
🔑 key pending…
CityCare Pharmacy
Pharmacy · New York
🔑 key pending…
Lot VX-2481 custody trail
0 pendingNo events yet. Ship the lot to follow a vaccine batch from the Basel plant to a New York pharmacy. Every handoff and temperature reading is signed by the organization responsible for it.
Shared ledger
The ledger is empty. Blocks appear here as signed events are batched under a Merkle root and sealed by rotating validators, with one copy per organization so no single party controls the record.
How it works
Digital signatures
Each organization holds an ECDSA P-256 keypair generated in your browser. Every custody handoff and temperature reading is signed by the party responsible, so nobody can write history in someone else's name.
Merkle trees
Event hashes are pairwise-hashed up to a single Merkle root per block, so one root commits to every record and any edited event breaks the proof.
Proof-of-authority
Public chains burn energy on proof-of-work; consortium chains like this one rotate block sealing among known, accountable validators instead. Each block carries its sealer's signature, the honest choice when the members are known.
Why a blockchain at all?
The ledger is replicated across four organizations that don't fully trust each other. A plain database has an admin who can quietly rewrite it; here, no single party can edit or forge a record without every other member's copy exposing it.