thumb|"Chrome plated" motorcycle parts, plated with a decorative layer of chromium Chromium is a chemical element; it has symbol Cr and atomic number 24. It is the first element in group 6. It is a
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 0x0b3d4216decb74968b6f238d8f95c44feb408464a38381c851927714e690fe3d. Chain 2 (Bitcoin): anchored in block 954631 (2026-06-21T02:46:24Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/d144cb66-54e8-4a86-8d19-9110113fb971.json and https://artists.proofprofile.net/proofs/artist/d144cb66-54e8-4a86-8d19-9110113fb971.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).