Leonid Borisovich Kogan (; ; 14 November 1924 – 17 December 1982)Boris Schwarz and Margaret Campbell. "Kogan, Leonid." Grove Music Online. Oxford Music Online. Oxford University Press, accessed Novemb
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 0xa324ee1d835f104fd823018bdd75da15362bf7077a84f8eef7adb38faa4be1d9. Chain 2 (Bitcoin): anchored in block 953741 (2026-06-15T04:44:49Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/9fcca064-5264-4d7f-9e31-7fb9e0f04a8b.json and https://artists.proofprofile.net/proofs/artist/9fcca064-5264-4d7f-9e31-7fb9e0f04a8b.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Mendelssohn & Beethoven: Violin Concertos
Tchaikovsky: Trio pour piano, violon et violoncelle & Quatuor à cordes No. 3 (Les indispensables de Diapason)
Telemann: Canon-Sonata for Two Violins in G Major, TWV 40:118: I. Vivace
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x59e67d629e8fec1c40f8a2d21ea67138e76ed9989e96ffe0e89150fe914b5fe7. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400363.
Telemann: Canon-Sonata for Two Violins in G Major, TWV 40:118: II. Adagio
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4b21e929565cf6bb820008ef66031592c3109932902da3389125a9bac485d1ce. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400364.
Telemann: Canon-Sonata for Two Violins in G Major, TWV 40:118: III. Allegro
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb233e940fab4f16b796b1a815538a975f184ac8c3036988d0b8eb23c123ea152. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400365.
Brahms: Violin Sonata No. 1 in G Major, Op. 78: II. Adagio
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x470733d3f367bd226f70df325c00c8f41ddd42ed36ca8fec13c96be919ea908a. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/GBAYC0502039.
Leclair: Sonata for Two Violins in G Major, Op. 3 No. 1: I. Allegro
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x215397bec97d9cf67241e4d3f2128f9577476266eb3cf679e27c0734bfd31613. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400360.
Leclair: Sonata for Two Violins in G Major, Op. 3 No. 1: III. Allegro
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x49dc8b1054eeb02655199a967cb291072945a6fd927ae4c1534823b14429fa24. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400362.
Locatelli / Arr. Ysaÿe: Violin Sonata in F Minor, Op. 6 No. 7 "At the Tomb": III. Lento
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0819f042d74dac99978e0ee6503c22e1dcd803331363d152605e91f3b744c9c8. 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/FRZ111400355.
Leclair: Sonata for Two Violins in C Major, Op. 3 No. 3: III. Allegro
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd44ade69470ff79360e8601212e9d47a0b144e32b025d0cd865a754a87b09319. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400359.
Brahms: Violin Sonata No. 2 in A Major, Op. 100: II. Andante tranquillo - Vivace
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x51dfd37ac4ccbcbf70d2d335749b7b6ff1a53ab0b56d148a2a18a2685a0380fc. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/GBAYC0502043.
Ysaÿe: Sonata for Two Violins in A Minor: I. Poco lento maestoso - Quasi moderato
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1e4e06d39be52be76df72d6c43e796a51b9a6f3e9be6823e84c20b16318aafa7. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400366.
Bach: Violin Partita No. 1 in B Minor, BWV 1002: V. Sarabande
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x65597672b24fb695b81a0611fe92745599f8190ada903d81702d5e320f0bb127. Chain 2 (Bitcoin): anchored in block 960334 (2026-07-31T02:19:15Z), 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/GBAYC0800071.
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
Paganini: Cantabile for Violin and Piano in D Major, Op. 17
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x02f2a8019c9c8d6ec1f092caee6f751692e600c6681919e85a2f288fed5d12c3. Chain 2 (Bitcoin): anchored in block 960273 (2026-07-30T15:42:38Z), 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/FRZ111200530.
Brahms: Violin Sonata No. 1 in G Major, Op. 78: I. Vivace ma non troppo
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x411ad443cce6a5c4ade994ff80e8d1e83cc2e8abf448103ae3c38320c0bee17e. Chain 2 (Bitcoin): anchored in block 960300 (2026-07-30T19:42:40Z), 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/GBAYC0502038.
Brahms: Violin Sonata No. 1 in G Major, Op. 78: III. Allegro molto moderato
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x968f44724453f6938a633fc502b90a9b344ea1c234df9c6be6b515846fbe6160. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/GBAYC0502040.
Leclair: Sonata for Two Violins in G Major, Op. 3 No. 1: II. Allegro ma poco
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd29f95f4e1c94748539cac0e301a09c0cb8bc3404ff61a1b29eaf19206cee004. Chain 2 (Bitcoin): anchored in block 960418 (2026-07-31T15:20:15Z), 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/FRZ111400361.
Locatelli / Arr. Ysaÿe: Violin Sonata in F Minor, Op. 6 No. 7 "At the Tomb": I. Lento assai e mesto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9961b0facf5bf90f3c892c838eadebf46d90b853f7bf1dc01c659d4066820b86. Chain 2 (Bitcoin): anchored in block 960441 (2026-07-31T17:29:52Z), 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/FRZ111400353.
Locatelli / Arr. Ysaÿe: Violin Sonata in F Minor, Op. 6 No. 7 "At the Tomb": II. Allegro
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x67045bba37d3c3e99facce01df1f67f1c930f2f4b231c1ba84852fe2bbf55e64. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400354.
Locatelli / Arr. Ysaÿe: Violin Sonata in F Minor, Op. 6 No. 7 "At the Tomb": IV. Tempo moderato
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcfa5e2ad3d3b518e3e7cfd5446daf2141e57b21cae7c1881fbb6bde9a2474320. Chain 2 (Bitcoin): anchored in block 960459 (2026-07-31T20:22:46Z), 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/FRZ111400356.
Leclair: Sonata for Two Violins in C Major, Op. 3 No. 3: I. Adagio - Vivace
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xccaa3a3da5fd55dad37af72edc0c30272a4475798ab0f903fb3127572f9ec9dc. Chain 2 (Bitcoin): anchored in block 960418 (2026-07-31T15:20:15Z), 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/FRZ111400357.
Leclair: Sonata for Two Violins in C Major, Op. 3 No. 3: II. Adagio
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9cb77b247cb16693740c146db49682124a0a30417b78b1c06aedf18261a0aeb6. Chain 2 (Bitcoin): anchored in block 960258 (2026-07-30T12:45:34Z), 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/FRZ111400358.
Ysaÿe: Sonata for Two Violins in A Minor: II. Allegretto poco lento
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x46bd980d1210952b0a307bc3cec6ae340002aca28865551a614d8ed5973eb1c6. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400367.
Ysaÿe: Sonata for Two Violins in A Minor: III. Allegro vivo e con fuoco - Moderato amabile
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8207d231d96d95b89a5bbc57c69f5533ab5c228fb5ce79775a886be492ad950a. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRZ111400368.