thumb|Musical notation for the chorus of "Jingle Bells" A refrain (from , "to repeat", through ) is the line or lines that are repeated in poetry or in music—the "chorus" of a song. Poetic fixed for
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 0xea257619019efda93be340714af1db43d6d2e2f4986273b707a9fc3a82cce74c. Chain 2 (Bitcoin): anchored in block 954014 (2026-06-16T22:46:20Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/30137481-3fcf-45d0-b217-932eb96b9dda.json and https://artists.proofprofile.net/proofs/artist/30137481-3fcf-45d0-b217-932eb96b9dda.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).