thumb|The weave of calico sample from a shopping bag shown against a centimetre scale Calico (; in British usage since 1505) is a heavyOxford Advanced Learner's Dictionary of Current English ISBN 019
1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5d65e24109b1eded6751e4b47ea2fe2c92034571ec7411fb1da42a3282117381. Chain 2 (Bitcoin): anchored in block 954667 (2026-06-21T07:29:20Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/def2b29e-9c4c-4f9b-a722-218da1b4c16b.json and https://artists.proofprofile.net/proofs/artist/def2b29e-9c4c-4f9b-a722-218da1b4c16b.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).