thumb|Brass buttons from the uniform of a Danish World War I artillery lieutenant thumb|Modern buttons made from vegetable ivory A button () is a fastener that joins two pieces of fabric together by
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 0x2af5f48c612e762b52e57e351a5dd43dedc6f53f8b68d46162d5fb90dd78d714. Chain 2 (Bitcoin): anchored in block 954603 (2026-06-20T21:47:54Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/c37bbf63-3db4-45d6-8ba5-86760891717a.json and https://artists.proofprofile.net/proofs/artist/c37bbf63-3db4-45d6-8ba5-86760891717a.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).