thumb|Portrait of de Croes, 1747 Henricus Jacobus de Croes, Hendrik Jacob de Croes, known as Henri-Jacques de Croes (baptised 19 September 1705 in Antwerp, died 16 August 1786 in Brussels) was a Flemi
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x629897d37724e3167bf7b37cb38b6ff5a5ad964ac7bac1e1a0ad4bc207a62f83. Chain 2 (Bitcoin): anchored in block 954729 (2026-06-21T18:16:07Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/fad1bf76-6308-473d-9917-e8541a587908.json and https://artists.proofprofile.net/proofs/artist/fad1bf76-6308-473d-9917-e8541a587908.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Henri-Jacques de Croes: La Sonate Égarée
De Croes: Brussels, 1734: VI Concerti for Violin