thumb|Yolandi Visser wearing a zef T-shirt Zef () is a South African counter-culture movement. Etymology Yolandi Visser of Die Antwoord said, "It's associated with people who soup their cars up and
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 0x41954a1d8f3e5b8845f7ba8b5a1253a1067a26bab1fc615d8c642e76fa443b1e. Chain 2 (Bitcoin): anchored in block 954065 (2026-06-17T08:10:43Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/4fdb806e-fe82-4331-9875-b483392ce981.json and https://artists.proofprofile.net/proofs/artist/4fdb806e-fe82-4331-9875-b483392ce981.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).