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 0x66c2f93533a812042f2d56d477a6d4da73d81ed7a46dbf2c7296c6912870895e. 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/4f1740f0-85cd-4534-b448-c922bf60c7af.json and https://artists.proofprofile.net/proofs/artist/4f1740f0-85cd-4534-b448-c922bf60c7af.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Haydn: Sonatas No. 23, No. 34, No. 37 & No. 50
Haydn: Sonata No. 50 - Tchaikovsky: Symphony No. 6
Haydn: Piano Sonata in C Major, Hob. XVI:50 (Digitally Remastered)
Haydn: Piano Sonata in E Minor, Hob. XVI:34 (Digitally Remastered)
Haydn: Piano Sonata in D Major, Hob. XVI:37 (Digitally Remastered)
Haydn: Piano Sonata in F Major, Hob. XVI:23 (Digitally Remastered)