thumb|Altitude is a vertical measurement between a reference datum and an object. Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point o
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 0x21cfd561fe4c3baf9518439807f7f4a3893ee1c7d696d085e978eaf15b11d7eb. Chain 2 (Bitcoin): anchored in block 953407 (2026-06-12T19:24:56Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/cbb5b11d-c0c1-4051-9ed9-16d181415df0.json and https://artists.proofprofile.net/proofs/artist/cbb5b11d-c0c1-4051-9ed9-16d181415df0.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).