Yvonne Lefébure (29 June 1898, Ermont – 23 January 1986, Paris) was a French pianist and teacher. Early life and education Lefébure began studying piano with a local teacher. In 1906, she was intro
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 0x70394c0c4c4004db653e2ac7a66d4a0b412eac7466a8fa1a9d8f4947bd7ef9e6. Chain 2 (Bitcoin): anchored in block 954689 (2026-06-21T10:35:31Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/e36ec4d4-f5a3-44df-be09-924c75e39c55.json and https://artists.proofprofile.net/proofs/artist/e36ec4d4-f5a3-44df-be09-924c75e39c55.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
Women at the Piano - An Anthology of Historic Performances, Vol. 4 (1921-1955)
Mendelssohn - Schumann - Pierné - Loucheur, Concert du 04/04/1955, Orchestre National, Pierre Dervaux (dir), Y. Lefébure (piano)
Beethoven: Piano Concerto No. 4 in G Major, Op. 58 & Piano Works & Sonatas for Violin & Piano
Mozart: Piano Concerto No. 20, K. 466, Yvonne Lefébure vs. Rudolf Serkin (Compare 2 Versions)
Mozart: Piano Concerto No. 20 - Beethoven: Symphony No. 6
Lutoslawski - Beethoven - Chostakovitch, Orchestre national de la RTF - Yvonne Lefébure (piano)
Debussy: La Boîte à Joujoux, L. 128, Bach: Prelude and Fugue No. 3 in C-Sharp Major, BWV 848 & Concerto for Piano and Orchestra in D Minor, BWV 1052
Couperin, Debussy, Roussel : Œuvres pour piano
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 0xf2b57659b1890afc87bfaa9dd7b7bb95468bba67091100f5e6f89165aaa2ff5f. 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/FRY830809730 — a six-check JSON result.
Beethoven : Sonates pour piano op. 106 "Hammerklavier" & op. 111
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9b8192c24a5c89a950495f9e69fe717e52aaa95e01cfeca3c2d1610cbab6c789. Chain 2 (Bitcoin): anchored in block 960266 (2026-07-30T14:44:50Z), 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/FRY830709460 — a six-check JSON result.
Schubert: Piano Sonata No. 21 in B-Flat Major, D. 960 - Schumann: Davidsbündlertänze, Op. 6
Orgelbüchlein (Little Organ Book): Choral in C Minor, BWV 639 “Ich ruf’ zu dir Herr Jesu Christ”
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xabdaa6c30f9703570b53526fcff27713d78e1f6433011044f1104fdf031309f7. 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/FRY837805010 — a six-check JSON result.
Well-Tempered Keyboard, Book 1: 8. Prelude and Fugue in E-Flat Minor, BWV 853
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd82cd9f2b14a3a1aa4724e7d2bed09dd9d9e3794328ef49cee3c25b6f89412ba. Chain 2 (Bitcoin): anchored in block 960404 (2026-07-31T13:06:57Z), 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/FRY837805030 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x04202f90c68d549cc58277dea8929d91a8a66809bbb241c1173564e44fb570fb. 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/FRY837805130 — a six-check JSON result.
Ravel: Le Tombeau de Couperin & Jeux d’eau & Other Piano Works
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7849c001b58cd08d932a8f3e165946d12ca06a9d34593662db079a851692873f. 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/FRY837505000 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf2840a43b296531c0b10d6fa9aae98ba145ea0ce773347b8f83afd073737d039. 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/FRY837505010 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa84ea438b4435e7b9f11a96de0d9e3c4c413a38a709cc4e5a5d0fde13d15dc9d. Chain 2 (Bitcoin): anchored in block 960497 (2026-08-01T02:22:04Z), 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/FRY837505020 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5e9ab63ccacb4708fb68cc2a5e641c531a3f87ce69c9c582f34472ccac66cb34. 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/FRY837505030 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x947818490d5f32bf11e102af4891da693aa9d10dbe801e732fc9661f288f25bb. 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/FRY837505040 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9ee1d62ac53ad2aee74b67b5fc9bc5503cfe7f09211f7115064fd969eb7c88cb. 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/FRY837505050 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x618e2f105488572960dc5f92a93372df2b7a41aeebf36b6508a6fbb0eb7b3807. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRY837505060 — a six-check JSON result.
Ma Mère l’Oye: III. Laideronnette, Impératrice des pagodes
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8cf3ea4a6d67fb4075df26c1d4bafa80266846c9cf64877e1cbe6b09db4503b2. Chain 2 (Bitcoin): anchored in block 960337 (2026-07-31T02:51:48Z), 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/FRY837505090 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbcd0bee46b682814fcbe028c3a9ccaab95ecf5f60f8517584a129a59c10239d3. Chain 2 (Bitcoin): anchored in block 960222 (2026-07-30T07:48:45Z), 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/FRY837505110 — a six-check JSON result.
Suite for Keyboard in A Minor: VII. Gavotte and Six Doubles
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xaec5b44ed3b6d996dbf1a1a7a65f457cbd0be53e92f383ae3821aa53278dc5f2. Chain 2 (Bitcoin): anchored in block 960138 (2026-07-29T19:35:34Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRY837105140 — a six-check JSON result.
Beethoven: Piano Sonatas Nos. 30 & 31 (Mono Version)
Beethoven: 33 Variations sur une valse de Diabelli (Mono Version)
Debussy: La boîte à joujoux (Mono Version)
Wilhelm Furtwängler, conductor • Berliner Philharmoniker • Yvonne Lefébure, piano : Mozart • Beethoven
Mozart: Piano Concerto No. 20 in D Minor, K. 466
Bach: Transcriptions for Piano (Mono Version)
Ravel: Sonate pour violon et piano, M. 77 (Mono Version)
Pablo Casals Dirige Bach: For Festival de Prades 1950
Branderburg Concerto No. 3, in G Major, BWV 1048: I. Allegro moderato
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdeca72d813bc45355c8d1c499452c8a610950d094568f1a5e7f2f7b10af71772. Chain 2 (Bitcoin): anchored in block 956302 (2026-07-02T03:30:09Z), 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/FR6V81442224 — a six-check JSON result.
Ravel: Les chefs-d'œuvre - La discothèque idéale de Diapason, Vol. 32
Roussel: Symphonie No. 3, Suite en Fa, Sinfonietta pour cordes (Les indispensables de Diapason)
Mozart: Concerto No. 20 for Piano and Orchestra in D Minor, K. 466
Beethoven, L. Van: Symphony No. 6 / Mozart, W.A.: Piano Concerto No. 20 / Schubert, F.: Symphony No. 8