Sjoerd () is a Dutch masculine given name of West Frisian origin. It is derived via Sieuwerd from the Germanic Sigiward ("victory warden"). Sjoerd gained some popularity as a baby name between 1975 an
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 0xab2e68ba3b1f73baad961fe0c867993daf97bb2a2b746cece77b37174c213636. Chain 2 (Bitcoin): anchored in block 954587 (2026-06-20T19:10:41Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/bb90d3cd-3f33-4d8e-b80a-fd818cd2f5bb.json and https://artists.proofprofile.net/proofs/artist/bb90d3cd-3f33-4d8e-b80a-fd818cd2f5bb.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).