Jan de Hartog (April 22, 1914 – September 22, 2002) was a Dutch playwright, novelist and occasional social critic who moved to the United States in the early 1960s and became a Quaker. Early life I
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 0xf0df9b9c99659c2fe305f35a76689f79ca77b719ebc8839cb927c5d1837c3bd7. Chain 2 (Bitcoin): anchored in block 954603 (2026-06-20T21:47:54Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/c439cdb5-974c-465e-bf23-0be007e127e7.json and https://artists.proofprofile.net/proofs/artist/c439cdb5-974c-465e-bf23-0be007e127e7.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).