Frank Guarrera (December 3, 1923 – November 23, 2007) was an Italian-American lyric baritone who enjoyed a long and distinguished career at the Metropolitan Opera, singing with the company for a total
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 0x15a49f0cd99858c704121c5de205a8aea8443547db220cbf9b692268512acd63. 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/e3650520-c666-466e-8306-6af1423f46d8.json and https://artists.proofprofile.net/proofs/artist/e3650520-c666-466e-8306-6af1423f46d8.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
Donizetti: Lucia di Lammermoor, A. 46 (Excerpts)
Chorus and Orchestra of the Metropolitan Opera Association
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 0xe1a629b053be456b32683f6c354c3119481cfa87052c77e843dca1cd91fec21d. Chain 2 (Bitcoin): anchored in block 960478 (2026-07-31T23:30:38Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/ATP130201512 — a six-check JSON result.
Faust, CG 4, ICG 61, Act I: "Introduction"
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfb40288052d8e2882f25f411b97ffb14db578ca852d9138c9dfc12a5ba82830f. 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/ITE012106906 — a six-check JSON result.
Faust, CG 4, ICG 61, Act III: "Eh quoi! toujours seule?" (Faust, Marguerite, Méphistophélès, Marthe)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x506a2774514fbcf94f1ea1d55f24e10986a3c1428c0ca305f75bf6909326cf04. Chain 2 (Bitcoin): anchored in block 960456 (2026-07-31T19:53:57Z), 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/ITE012106936 — a six-check JSON result.
Faust, CG 4, ICG 61, Act III: "Il était temps! Sous le feuillage sombre" (Méphistophélès, Marguerite, Faust)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9891590d825f962401a1c8c1ea74ef2b084a634e410444407499554695c15bba. 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/ITE012106938 — a six-check JSON result.
Faust, CG 4, ICG 61, Act I: "Me voici! D'où vient ta surprise?" (Méphistophélès, Faust)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x38d24584816f401ef82589546ccbb1d180cfe916ac311a91c1e2c81c393b4a0d. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/ITE012106911 — a six-check JSON result.
Faust, CG 4, ICG 61, Act I: "A moi les plaisirs" (Faust, Méphistophélès)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb7d29aae9bfa4d4a186b21d37a29ccf521fd8f338a304866c7118b1251acb7cb. Chain 2 (Bitcoin): anchored in block 960427 (2026-07-31T15:59:18Z), 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/ITE012106912 — a six-check JSON result.
Faust, CG 4, ICG 61, Act I: "O merveille!" (Faust, Méphistophélès)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x12a945061fc430cd47d449a03aceedbf5597135976ed6fd2ea1d15cca628a400. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/ITE012106913 — a six-check JSON result.
Faust, CG 4, ICG 61, Act III: "Tête folle!" (Méphistophélès, Faust)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc3c6ec9896c4bbdeca4979b1619d6208d47cb51cf8cd534b542513baf8fd2e34. 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/ITE012106942 — a six-check JSON result.
Faust, CG 4, ICG 61, Act I: "Veins?... Je la reverrai?" (Méphistophélès, Faust)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe8fc79908a4c03b1a9200095c5a5876112917f5c6260a623f093b7309f81aa5e. 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/ITE012106914 — a six-check JSON result.
Faust, CG 4, ICG 61, Act II: "Avant de quitter ces lieux" (Valentin)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3158b2aa629253e38e8a172cbe0d7291ce343b494d5df8404cbbc2bfa58d5c13. 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/ITE012106917 — a six-check JSON result.
Faust, CG 4, ICG 61, Act II: "Allons, amis! point de vaines alarmes" (Wagner, Chœur, Méphistophélès)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x77d9ad8a7a5d8f474ad7c9361ab9e8554c41a2f4e80caf9651fb044cd780e8ef. Chain 2 (Bitcoin): anchored in block 960403 (2026-07-31T13:04:34Z), 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/ITE012106918 — a six-check JSON result.
Faust, CG 4, ICG 61, Act II: "Le veau d'or est toujours debout!" (Méphistophélès, Chœur)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe4863be1d312822208032d614090f58fcea3b59472f6c2b87ff9146b7afcb75e. 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/ITE012106919 — a six-check JSON result.
Faust, CG 4, ICG 61, Act II: "Merci de ta chanson!" (Chœur, Valentin, Wagner, Méphistophélès, Siebel)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2bd65a7ad641ec7420f323a63817268a7d6801562090aae3ffb8c317a057dd17. 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/ITE012106920 — a six-check JSON result.
Faust, CG 4, ICG 61, Act II: "Nous nous retrouverons, mes amis!" (Méphistophélès, Faust)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5695b34e987fffc597dcc41b4c03984abf3a7c247709880523248b1445190f09. 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/ITE012106921 — a six-check JSON result.
Faust, CG 4, ICG 61, Act II: "Ainsi que la brise légère" (Chœur, Méphistophélès, Faust, Siebel)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfedd465f290bca640286a5a6ad9dbcebafa06cf4b14fa874de34ba73c4fd72b9. 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/ITE012106922 — a six-check JSON result.
Faust, CG 4, ICG 61, Act II: "Ne permettez-vous pas" (Faust, Marguerite)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdfec4854785b8864dd1223ad95f9a1579d975571dfb9cd66565da2d2116e439f. Chain 2 (Bitcoin): anchored in block 960478 (2026-07-31T23:30:38Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/ITE012106923 — a six-check JSON result.
Gounod: Faust (Bjorling, Siepi, Kirsten) (1950)
Mozart: Le nozze di Figaro, K. 492 (Live)
Donizetti: L'Elisir d'Amore (Metropolitan Opera)
Lucia di Lammermoor, Act II: Tu che a Dio spiegasti
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6bd091759c621e14b83d6b914517ab65a631e5dee4858e48ecfd24aae81d5650. Chain 2 (Bitcoin): anchored in block 957050 (2026-07-07T14:41:13Z), 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/QM6N21446093 — a six-check JSON result.
Jussi Bjorling in Two Puccini Operas (1948, 1956)
Dio! mi potevi scagliar tutti mali della miseria (Othello)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa692ef98cc39d54554f5ccc9004bdd87d34a298103c3250afd5cc0a49258ea09. 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/ATP130561908 — a six-check JSON result.
Mozart: Le Nozze di Figaro (The Marriage of Figaro), K. 492
Verdi: Falstaff (Rehearsals) (Toscanini) (1950)
Mozart: Così fan tutte, K. 588 (Sung in English) [Live]
Mascagni: Cavalleria rusticana (Mono Version)
Verdi: Les plus beaux airs d'Otello (Mono Version)
Arturo Toscanini collection - Volume 57 (Falstaff)
Mascagni: Cavalleria Rusticana & Leoncavallo: Pagliacci (Remastered)
Donizetti: Lucia di Lammermoor (Remastered)