Zeta (, ; uppercase Ζ, lowercase ζ; (Ancient Greek and Katharevousa: ζῆτα, , classical or zē̂ta; zíta) is the sixth letter of the Greek alphabet. In the system of Greek numerals, it has a value of
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 0x284e4e214319bb769de6897ed1e96a837d84cf2dbb7c1a066b9d61e0f437cc44. Chain 2 (Bitcoin): anchored in block 954728 (2026-06-21T18:08:38Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/f8af8d60-7cba-445a-ae45-53ceeb2c80a3.json and https://artists.proofprofile.net/proofs/artist/f8af8d60-7cba-445a-ae45-53ceeb2c80a3.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).