Mark W. Billman (March 10, 1905 – May 30, 1933) was an American racing driver. He was killed 79 laps into the 1933 Indianapolis 500, his only Championship Car start. Death On his seventy-ninth lap
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 0xb555f89b1624747cef8da83bce95800a76c3db27b20241d0f8299ad44e95008d. Chain 2 (Bitcoin): anchored in block 954065 (2026-06-17T08:10:43Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/515fbfaa-a1d3-406b-b0cd-eef35e43b0b3.json and https://artists.proofprofile.net/proofs/artist/515fbfaa-a1d3-406b-b0cd-eef35e43b0b3.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).