William David Hamilton Sellar (27 February 1941 – 26 January 2019) was a legal historian who served as Lord Lyon King of Arms from 2008 to 2014. Sellar studied history at Oxford University graduatin
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 0x9a5b17fe77e4af3bf28f7f5755e9d48b47d1b5b32e4d77cdf3b1e10b00dfcb3f. Chain 2 (Bitcoin): anchored in block 954555 (2026-06-20T12:10:20Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/ad89dbc1-7a89-4ced-beec-c322c181c4b3.json and https://artists.proofprofile.net/proofs/artist/ad89dbc1-7a89-4ced-beec-c322c181c4b3.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).