Janszoon usually abbreviated to Jansz was a Dutch patronym ("son of Jan"). While Janse, Janssens, and especially Jansen and Janssen, are very common surnames derived from this patronym, the form Jansz
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 0xf75bb85a495e83d15dc7081e23a346756a30ae4fe28cef5284c3441b5f5aba9c. Chain 2 (Bitcoin): anchored in block 954615 (2026-06-20T22:44:50Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/c5eb608f-312d-426f-8036-275c74ad1a5c.json and https://artists.proofprofile.net/proofs/artist/c5eb608f-312d-426f-8036-275c74ad1a5c.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).