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 0x32042da7873b597fe522c0d176865e38aa98e1361ec56cc724824462894d484b. Chain 2 (Bitcoin): anchored in block 954093 (2026-06-17T12:13:19Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/7aa476a6-18ad-4208-b3e1-ac09a3da8610.json and https://artists.proofprofile.net/proofs/artist/7aa476a6-18ad-4208-b3e1-ac09a3da8610.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Beethoven: Complete String Quartets by the Hungarian String Quartet (2023 Remastered, Paris 1953)
Beethoven String Quartets, Vol. 7: No. 12 in E-Flat Major, Op. 127 & No. 16 in F Major, Op. 135
Beethoven String Quartets, Vol. 3: No. 5 in A Major, Op. 18 No. 5 & No. 6 in B-Flat Major, Op. 18 No. 6
Beethoven String Quartets, Vol. 2: No. 3 in D Major, Op. 18 No. 3 & No. 4 in C Minor, Op. 18 No. 4
Beethoven String Quartets, Vol. 1: No. 1 in F Major, Op. 18 No. 1 & No. 2 in G Major, Op. 18 No. 2
Bartók: String Quartet No. 5 - Schubert: String Quartet No. 15 in G Major (Live)
Hungarian String Quartet / Zoltan Szekely play: Pyotr Tschaikowski / Alexander Borodin: String Quartet No. 1 / String Quartet No. 2
Hungarian String Quartet play: Joseph Haydn: String Quartet, op. 76 no. 2 - "Fifths", Hob. III:76 / String Quartet, op. 64 no. 5 - "Lark", Hob III:63
Schubert: String Quartet No. 14, D. 810, Hungarian Quartet vs. Wiener Konzerthausquartett (Compare 2 Versions)
Schubert: Quartet No. 13, Op. 29, D. 804, Hungarian Quartet vs. Wiener Konzerthausquartett (Compare 2 Versions)
Schubert: String Quartets Nos. 13 - 15 & String Quintet
Schubert: String Quartet No. 13 in A Minor, Op. 29, D. 804 "Rosamunde": I. Allegro ma non troppo
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 0x1f91577ac88c611ae723bf150a91d23fb28de4d59716653d2ae72fd6a9d70125. Chain 2 (Bitcoin): anchored in block 960489 (2026-08-01T00:40:43Z), 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/FRZ115904260.
Schubert: String Quartet No. 14 in D Minor, D. 810 "Death and the Maiden": II. Andante con moto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9ee0db01cca7f4237f8e2af22f55a309988c0fc0bbb093fec8a68cc936aee431. 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/FRZ115904350.
Haydn: String Quartet No. 82, Op. 77 & No. 5, Op. 64
Debussy & Ravel: Quatuors à cordes (Mono Version)
Mozart: String Quartets No. 17, K. 458 "The Hunt" & No. 19, K. 465 "Dissonance" (Mono Version)
Mozart: Quatuors à cordes Nos. 16 & 18 (Mono Version)
Haydn: Quatuors à cordes, Op. 64 No. 5 & Op. 77 No. 2 (Mono Version)
Bartók: 6 Streichquartette (Mono Version)
Dvořák: Quintette pour piano et cordes No. 2, Op. 81 (Mono Version)
Dvořák: Quintette pour piano et cordes No. 2 (Stereo Version)
Brahms: Quatuors à cordes Nos. 1 & 2 (Mono Version)
Schubert: Quatuor à cordes No. 13 "Rosamunde" - Dvořák: Quatuor à cordes No. 12 "Américain" (Mono Version)
Franck: Quintette pour piano et cordes (Mono Version)
Mozart: String Quartets Nos. 16 & 18 (Mono Version)
Morceaux choisis de quatuors à cordes (Mono Version)
Haydn: Quatuors à cordes "Des quintes" & "L'alouette" (Mono Version)
Borodin: Quatuor à cordes No. 2 - Tchaikovsky: Quatuor à cordes No. 1 (Mono Version)
Quartet No. 16 in F Major, Op. 135: IV. Grave, ma non troppo tratto - Allegro
Beethoven: Quartet No. 6 in B-Flat Major, Op. 18 No. 6: IV. La Malinconia. Adagio - Allegretto quasi allegro
Beethoven: Quartet No. 6 in B-Flat Major, Op. 18 No. 6: III. Scherzo. Allegro
Beethoven: Quartet No. 6 in B-Flat Major, Op. 18 No. 6: II. Adagio, ma non troppo
Beethoven: Quartet No. 6 in B-Flat Major, Op. 18 No. 6: I. Allegro con brio
Beethoven: Quartet No. 5 in A Major, Op. 18 No. 5: IV. Allegro
String Quartet No. 14 in D Minor, D. 810 'La Jeune Fille et la mort': II. Andante con moto