Longson is a surname. Notable people with the surname include: Harry Longson (1907–?), South Australian caricaturist O'Neil Longson, American poker player Sam Longson (died 1989), British businessman
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 0x438acb61c142ad3e912d79ed0cf5a4615260055b20d1cc052d9f22a2ffe87071. Chain 2 (Bitcoin): anchored in block 953909 (2026-06-16T07:53:13Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/0cb939d3-6413-4977-90a3-e1653a080eda.json and https://artists.proofprofile.net/proofs/artist/0cb939d3-6413-4977-90a3-e1653a080eda.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).