thumb|upright|A chair umpire prior to the start of a tennis match An umpire is an official in a variety of sports and competition who is responsible for enforcing the rules of the sport, including sp
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 0xe2c671d5d9b659cabd57491a1c7745ce231165cdd9ac93a3e8d3b5cf2561aa3f. Chain 2 (Bitcoin): anchored in block 954346 (2026-06-19T03:51:26Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/98c1e08e-43e1-4bda-ab2d-0943d6d41d44.json and https://artists.proofprofile.net/proofs/artist/98c1e08e-43e1-4bda-ab2d-0943d6d41d44.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).