David Longdon (17 June 1965 – 20 November 2021) was a British singer and multi-instrumentalist, who was best known as the lead vocalist and co-songwriter of the progressive rock band Big Big Train. Be
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 0xa5d675ffea44db74577ac5e353c9806238ae792a82ed50ba2cec10e844f537c5. 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/b1fb21c3-21c4-47f4-95a8-256a6fa5edc9.json and https://artists.proofprofile.net/proofs/artist/b1fb21c3-21c4-47f4-95a8-256a6fa5edc9.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).