Hendrik Otto "Henk" Westbroek (born 27 February 1952) is a Dutch musician, politician, radio host and entrepreneur. From 1979 to 1991, Westbroek was a vocalist for the pop group Het Goede Doel, one 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 0x5162a94bbe2e9e74429b7b5ec730b251750d2c9d2f4f93d7f82f9c1dfd9f8aed. 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/cd90b783-dc64-4020-8950-5f6df88f500e.json and https://artists.proofprofile.net/proofs/artist/cd90b783-dc64-4020-8950-5f6df88f500e.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.