Pierre Leduc or Le Duc (17 February 1755 – 18 October 1826) was a French violinist and music publisher, active from 1775 to 1811. Biography thumb|alt=signature de Leduc|The publisher's signature on
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 0x555d7ec37321e8afa867c6e2e749898a5afaa821b1ee8bc3cc1f7911af75eb09. 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/4e610b27-8581-40c8-bc7d-2b8d12cfb7bc.json and https://artists.proofprofile.net/proofs/artist/4e610b27-8581-40c8-bc7d-2b8d12cfb7bc.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).