ZK may refer to: Arts and entertainment ZK (rapper) (born 2000), Danish musician Zero-K, a 2010 real-time strategy game ZK, alleged publisher of Sad Satan, a 2015 horror game ZK, a 2014 Australia
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 0x5102d86361e372f95970acb74a3874d628023b45dd2f6f16c3fe492012560474. Chain 2 (Bitcoin): anchored in block 954650 (2026-06-21T04:51:12Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/d8c6e8e5-53f8-4942-b19b-1fbed9750a00.json and https://artists.proofprofile.net/proofs/artist/d8c6e8e5-53f8-4942-b19b-1fbed9750a00.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).