Nota Entitlements
Programmable onchain receipts that prove what an agent purchased and control how it’s redeemed.
Demo
About
Nota is a programmable receipt protocol for agent commerce. Payments prove that money moved, but they don’t prove what was actually purchased or what the buyer is entitled to afterward. Nota binds a seller-signed, itemized purchase commitment to an onchain payment, creating a verifiable receipt that can later be used as a credential for redemption. For ETHOnline, I extended Nota with an entitlement and redemption layer. A buyer can prove ownership of a valid receipt and redeem the purchased resource using a secret-based commitment. Possessing or stealing the receipt alone is not enough to redeem it, and successful redemptions cannot be replayed. The demo shows the complete flow: verifying the seller’s signed purchase data, purchasing through EIP-3009, creating the onchain receipt, rejecting an attempted redemption with only a stolen receipt, successfully redeeming with the correct secret, and rejecting a replay.
How it's made
Nota is built as a set of Solidity contracts on top of the existing Nota receipt protocol. The purchase flow uses seller-signed EIP-712 quotes and USDC EIP-3009 authorization for gasless-style payment settlement. Before purchasing, the client independently hashes the itemized document and verifies that it matches the metadata commitment signed by the seller, including checking that the line items equal the amount being charged. The ETHOnline work adds an entitlement/redemption layer on top of the receipt system. The buyer commits to a secret-derived purchase reference before purchase. After the receipt is created, redemption requires knowledge of the corresponding secret. The contracts reconstruct and verify the commitment, check receipt ownership and entitlement, and prevent the same redemption from being consumed twice. This separates payment, proof of purchase, and fulfillment while keeping them cryptographically connected.