Mark Clark may refer to: Mark A. Clark (politician) (born 1967), Arizona state legislator Mark A. Clark (general), U.S. Marine Corps general in charge of their Special Operations Command Mark W. Clar
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x25a1c40b2404df7d3c49f95c3dee666a0588beb5668dadb9b4cae14157960ad5. Chain 2 (Bitcoin): anchored in block 953423 (2026-06-12T21:20:00Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/82bad523-fa0b-4c8e-bc06-f5b604f5c939.json and https://artists.proofprofile.net/proofs/artist/82bad523-fa0b-4c8e-bc06-f5b604f5c939.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Celtic Clark, Mark and Philip Riley: Celtic Collection