thumb|upright=1.35|Double rainbow and supernumerary rainbows on the inside of the primary arc. The shadow of the photographer's head at the bottom of the photograph marks the centre of the rainbow cir
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 0xf2dacf5899e3272841dde5ff26174e1b9afdb7e2cefb63d29b4dcb3672073df7. Chain 2 (Bitcoin): anchored in block 954693 (2026-06-21T11:50:32Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/e56c78c1-6977-438d-80a6-c5ed7e5dd5e4.json and https://artists.proofprofile.net/proofs/artist/e56c78c1-6977-438d-80a6-c5ed7e5dd5e4.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).