The Berkel () is a river in the Netherlands and Germany. It is a right tributary of the IJssel. The river rises in Billerbeck, near the German city of Münster in North Rhine-Westphalia, and crosses t
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 0x140b08aef273114913bdc1bb652295b397c1ee4d6556f4368f9c60f02219c83d. Chain 2 (Bitcoin): anchored in block 954097 (2026-06-17T13:13:51Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/7b37a5fe-1ebe-4129-9774-2d5b88f6998d.json and https://artists.proofprofile.net/proofs/artist/7b37a5fe-1ebe-4129-9774-2d5b88f6998d.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).