John Koch (August 18, 1909 — April 19, 1978), (pronounced "KŌK") was an American painter and teacher, and an important figure in 20th century Realism. He is best known for his light-filled paintings 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 0x67d41c3d67e1bffed8638e1473d83adf4c7c7f131fc6ff4c901d09b59bf64fde. Chain 2 (Bitcoin): anchored in block 954066 (2026-06-17T08:11:48Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/78487ff9-21de-407c-930f-9ed7d71fe6c9.json and https://artists.proofprofile.net/proofs/artist/78487ff9-21de-407c-930f-9ed7d71fe6c9.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).