thumb|Tapestry showing Arthur as one of the Nine Worthies, wearing a coat of arms often attributed to him. 1385 King Arthur (; ; ; ) was a legendary king of Britain. He is a folk hero and a central f
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 Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe9f809444a020568451565fb93e92240c38d1c8eab15d6550d712ced286309f8. Chain 2 (Bitcoin): anchored in block 954623 (2026-06-20T23:40:06Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/ccab2b5c-4012-4ed2-8cd7-7d6418008a94.json and https://artists.proofprofile.net/proofs/artist/ccab2b5c-4012-4ed2-8cd7-7d6418008a94.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.