Abstract
A method for letting readers, and AI agents acting for readers, distinguish real first-hand purchase accounts from fabricated ones without revealing buyer identity. Each paid purchase is recorded on a blockchain as a commitment computed as plain SHA-256(nonce || buyerId), so the buyer can open and verify their own record with a single hash on any machine, without the chain's SDK or the seller's cooperation; the identity was measured on chain to match an externally computed digest byte for byte. Separately, a buyer who chooses to speak publicly can attach a plaintext account handle to one purchase as a second, insert-only record in a separate map; a binding cannot exist without its purchase, and a buyer who stays silent leaves no public trace. Both records carry a lot identifier, SHA-256("gyotak:lot:" || catch_report_id), linking the purchase to a published catch record and its cold-chain history, and a commitment is issued only when the shipped lot resolves to exactly one catch record. Timestamps are constrained to within 600 seconds of block time, preventing back-dating. Owner keys use per-contract domain tags. Verification paths are described, including the warning that an agent unable to issue a POST query must report "could not verify" rather than "no record exists".
Originally published 2026-09-17 as ECOSUS-TR-2026-015 at https://gyotak-tr.pages.dev/tr-2026-015/ ; archived at [Perma.ccのURL].
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Ogura, Takuya, "Anonymous Purchase Commitment with Optional Public Account Binding: Verifiable First-Hand Purchase Claims on a Public Ledger", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/11785