thumb|Horses hitched in tandem pulling a carriage Tandem, or in tandem, is an arrangement in which two or more animals, machines, or people are lined up one behind another, all facing in the same dire
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 0xcb02d615d55f7466ac09db34424ce477762b19e4b41d680fce3b4c3c39ef3558. Chain 2 (Bitcoin): anchored in block 954065 (2026-06-17T08:10:43Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/578991d6-177f-452f-ad04-7c61c4143016.json and https://artists.proofprofile.net/proofs/artist/578991d6-177f-452f-ad04-7c61c4143016.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).