Yaffa may refer to: Élie Yaffa (born 1976), French rapper known as Booba Sami Yaffa (born 1963), Finnish bass guitarist Yusupha Yaffa (born 1996), Gambian footballer Yaffa Ben-Ari (fl. 2017–2021)
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 0x966b4b6d3b59fefe3e653a2ba216dff82414a55d4f3acb193a2eadd7799a61fd. Chain 2 (Bitcoin): anchored in block 953407 (2026-06-12T19:24:56Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/4d611c9d-a541-4e35-bf35-0de8f2342c0a.json and https://artists.proofprofile.net/proofs/artist/4d611c9d-a541-4e35-bf35-0de8f2342c0a.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).