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 0x43b35c46a94aac4e73ea70c61be325664d469b731082fb32b06a13dcf4ceb25c. Chain 2 (Bitcoin): anchored in block 953778 (2026-06-15T11:57:35Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/cf2239bb-c58f-4fd4-b650-32165cc05b07.json and https://artists.proofprofile.net/proofs/artist/cf2239bb-c58f-4fd4-b650-32165cc05b07.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
1. Confirm isrcCode identifies the recording in the pre-2022 source corpus and cc-db-prod record 2. GET OTSVerificationAPI → server-side canonical-record, hash, and attestation checks must pass 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. Confirm CopyrightID is the CopyrightChains transaction hash 5. If all match: the cc-db-prod record is independently anchored on Bitcoin at OTSTimestamp 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 0x4cc51207b3ad277a57cf3e833bd978feda4973b7ffad652bf1e4e66f462be28f. Chain 2 (Bitcoin): anchored in block 958975 (2026-07-21T06:12:52Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZDA82192549 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1b638dea8c7c9769a162386c596ae8fc86750278ddb46402044582d55640762f. Chain 2 (Bitcoin): anchored in block 958319 (2026-07-16T20:12:32Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZK6H2014158 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbea2d0a3f852c357872c852e58801dc0ca6ab70a826d68276af6781899c0560e. Chain 2 (Bitcoin): anchored in block 959023 (2026-07-21T15:22:58Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QM6MZ2257327 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc26d7c59a7d3cb1152a3482351c2c5d91914f029a675907a94459c283f1a2803. Chain 2 (Bitcoin): anchored in block 958371 (2026-07-17T05:45:43Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QMDA62290011 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xad83cabdbfa5aa24efb5f0bdb336b4211f16771432de72297e68f853d0107d0c. Chain 2 (Bitcoin): anchored in block 956578 (2026-07-04T02:23:20Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/ITFHF2500010 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8dd4f25c62f54af452b23b389e03b31e8b7d6e0dfc1664f6ffe7e089740852a9. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/ITFHF2500120 — a six-check JSON result.