thumb|right|280px|Poseidon greeting Theseus (on the right). Detail, Attic red-figured calyx-krater by Syriscos Painter, 450-500BC from Agrigento. BnF Museum (Cabinet des médailles), Paris Poseidon (;
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 0xd4d612923d6c32fb2521912c7513f4d41e9fbf7e2ad8f9a3a32aa28be7c82544. Chain 2 (Bitcoin): anchored in block 953975 (2026-06-16T16:53:41Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/2baf2471-3b7b-48fd-a97a-c3daccb2cfde.json and https://artists.proofprofile.net/proofs/artist/2baf2471-3b7b-48fd-a97a-c3daccb2cfde.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).