Oskar Czerwenka (5 July 1924 – 1 June 2000) was an Austrian operatic bass and academic teacher. He was a member of the Vienna State Opera from 1951 to 1986, performing in 75 roles, including his signa
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 0x43281972c7b1838276d472a6a59394e3d43e3b457bc6f893ddbcfb9279efde3b. Chain 2 (Bitcoin): anchored in block 954066 (2026-06-17T08:11:48Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/7509cd62-8cfe-455a-b72e-acbd1231e822.json and https://artists.proofprofile.net/proofs/artist/7509cd62-8cfe-455a-b72e-acbd1231e822.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
Mozart: Le nozze di Figaro (Live in the Royal Festival Hall, 1954)
Le nozze di Figaro, K. 492, Act I: Overture - Live in the Royal Festival Hall, 1954
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 0x31ac40944bfce06b46ef646895244d00f868f2268cce701749980c40f335ae32. Chain 2 (Bitcoin): anchored in block 957145 (2026-07-08T08:56:20Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/GBG9M1501901 — a six-check JSON result.
Le nozze di Figaro, K. 492, Act IV Scene 13: Tutto è tranquillo e placido - Scene 14 Pace, pace, mio dolce tesoro! (Figaro, Susanna, Il Conte) - Live in the Royal Festival Hall, 1954
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9bb87ea1e25a6b146aecb599f4b9d5cc881562a20b7d603bacf1ca7ec22fc07a. Chain 2 (Bitcoin): anchored in block 960397 (2026-07-31T12:24:41Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/GBG9M1501859 — a six-check JSON result.
Gottfried von Einem: Der Prozeß, Op. 14 (Live)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x45ae04c73caeaabb70b4a1d6426993411dabe1fe556d247b75178a33a8ca3a8f. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101045 — a six-check JSON result.
Fidelio: Act I: Jetzt, Schätzchen, jetzt sind wir allein
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8bb72ce323b61e38bb703952c7b15c443b970148ecac3e93aa816c57637c7a3f. Chain 2 (Bitcoin): anchored in block 960368 (2026-07-31T08:26:41Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101046 — a six-check JSON result.
Fidelio: Der arme Jaquino ... O wär' ich schon mit dir vereint
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9534b04619e75d4d3e0773ee96b8c5497f76d7e8d3a33a8d892faa0355574b14. Chain 2 (Bitcoin): anchored in block 957120 (2026-07-08T03:22:41Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101047 — a six-check JSON result.
Fidelio: Guten Tag, Marzelline, ist Fidelio noch nicht zurückgekommen?
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcceaed08c3725550fbf87c25967a7ca955333e4a210f54d0eeeadad81f824571. Chain 2 (Bitcoin): anchored in block 960397 (2026-07-31T12:24:41Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101048 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x09096e3f0ce3b747700e21e334ac4574a8a4a8113da77caf48d566d80a68dce0. Chain 2 (Bitcoin): anchored in block 960317 (2026-07-30T21:35:24Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101049 — a six-check JSON result.
Fidelio: Höre, Fidelio - Hat man nicht auch Gold beneben
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x449930b04db10281a8c5e613eeeb7fa6ed1df9d4a1cfba617e130373db950a31. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101050 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x518d5b5c5943ea26fb2d93de124f23419b38c83d4d8ec69f2d2a36c6bb7d3728. Chain 2 (Bitcoin): anchored in block 960473 (2026-07-31T22:27:44Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101052 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x41320a932825df66fd704ace6486d41f8c0a8696e0c7939f6e1d7715212946fc. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101053 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x23969ad49955f3dae8ed429ac926e90af7aa7cdafa652dca30d793a4b6288f17. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101055 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3eb44b738f62ffa51f91f97d54c5200bf5ee2acb2f7e82d8815d14908c834e34. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101056 — a six-check JSON result.
Fidelio: Abscheulicher! Wo eilst du hin? - Komm, Hoffnung, lass den letzten Stern
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x31ddcbbba4a9dafa9af35817f76c51c46d12a5e267b723a3ef0cc2385268170e. Chain 2 (Bitcoin): anchored in block 960468 (2026-07-31T21:25:57Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101058 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa1c0f90be55e853990216f4c5fc4145c733389f5e48773e2d82e3655fc276efe. Chain 2 (Bitcoin): anchored in block 957124 (2026-07-08T03:53:27Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USSM11101059 — a six-check JSON result.
Richard Strauss: Les grands opéras - La discothèque idéale de Diapason, Vol. 7
Die Sänger der Wiener Staatsoper zur Wiedereröffnung des Hauses
Carl Loewe zu Ehren - Aufnahmen von 1902 - 1970
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x55af51b8186959adbf40b00068129d7a394334e65305498f5921b17ff26bea99. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/ATP139623027 — a six-check JSON result.
Paul van Kempen – Complete Philips Recordings
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbe15cdb2f9081262b0a51e1a97d9c837db2b1c2bd09388c52dfcead2bb5636a0. Chain 2 (Bitcoin): anchored in block 960108 (2026-07-29T13:09:35Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/NLA505100004 — a six-check JSON result.
Cornelius: The Barber of Baghdad (Mono Version)
Cornelius: The Barber of Bagdad (Der Barbier von Bagdad)
Cornelius: Der Barbier von Bagdad: Ouvertüre (Orch. Liszt & Mottl)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xabeac059da37bb9cc5a8c3d0eb7d4dc14422522c73fe37cc203382271a70ab27. Chain 2 (Bitcoin): anchored in block 960448 (2026-07-31T18:48:12Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/GBAYC2402367 — a six-check JSON result.
Cornelius: Der Barbier von Bagdad, Act 1: "Vor deinem Fenster" (Nureddin)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe9ccef85ef275e80a5164c385f853b21843d4a794f4c03153d6d154192a7d1b7. Chain 2 (Bitcoin): anchored in block 960247 (2026-07-30T10:42:33Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/GBAYC2402370 — a six-check JSON result.
Giuditta, Scene 1: Vorspiel. "Du meine schwarze Donna Antonia" (Pierrino, Chor)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x09513605f92fcb35ddfc62aa2cb6e2d4d54e1fa85c1ce640d4e0580ae8e9275e. Chain 2 (Bitcoin): anchored in block 960455 (2026-07-31T19:53:13Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEHB51284618 — a six-check JSON result.
Unvorbereitet - Ein ungewöhnlicher Liederabend
Ich Reise aus, meine Heimat zu entdecken - Ernstes und heiteres
Strauss, R.: Ariadne auf Naxos (Live at Festspielhaus, Salzburg Festival, 1954)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9be4a03e2460a7c1c78c1e663eb430ed347f7f88c3ea0ca1f328044bf96f49e2. Chain 2 (Bitcoin): anchored in block 960422 (2026-07-31T15:27:29Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/ATP139836212 — a six-check JSON result.
Mozart: Le nozze di Figaro (Mono Version)