thumb|Mark Hambourg, c. 1887–1897 Mark Hambourg (; 1 June 1879, in Boguchar, Voronezh Governorate – 26 August 1960, in Cambridge, United Kingdom) was a Russian British concert pianist.Eaglefield Hull,
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 0xebe19f671740bbee4e828c193fd9ab3814b970d01b07292ee79e39faa51249e2. Chain 2 (Bitcoin): anchored in block 954569 (2026-06-20T14:36:29Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/b161aa75-6e1e-4cca-94bb-71f95a32ee4c.json and https://artists.proofprofile.net/proofs/artist/b161aa75-6e1e-4cca-94bb-71f95a32ee4c.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Encores & Rarities - Selected HMV Recordings, 1910-1935
Schwanengesang. Piano Works by Leschetizky, Schubert and Saint-Saëns
"103 Classical & Conteporary Essentials" : Canzonetta
Chanson Triste, Op. 40, No. 2 - Duo-Art 5957
Rendezvous. Piano Revelations from the Golden Age
1. Confirm isrcCode identifies the recording in the pre-2022 source corpus and cc-db-prod record 2. GET OTSVerificationAPI → server-side canonical-record, hash, and attestation checks must pass 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. Confirm CopyrightID is the CopyrightChains transaction hash 5. If all match: the cc-db-prod record is independently anchored on Bitcoin at OTSTimestamp 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 0x995c68eadeb31b499af4206707e064fee71c25528371d2d82eb583f24ce17479. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEPI82401792.