Doublet is a word derived from the Latin duplus, "twofold, twice as much", and is used to indicate a pair of identical, similar, or related things. Doublet may refer to: Apparel Doublet (clothing),
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 0xc7ab431fc189b1e672afc3aed01231a619c80b73e07a492698a480d2c1c8bee1. Chain 2 (Bitcoin): anchored in block 953924 (2026-06-16T09:52:28Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1c3be5ab-43f7-4c44-91be-2dcedaa9d585.json and https://artists.proofprofile.net/proofs/artist/1c3be5ab-43f7-4c44-91be-2dcedaa9d585.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).