Klaus Hirte (28 December 1937 – 15 August 2002) was a German operatic baritone. Life Training Born in Berlin, Hirte grew up in Calw, learned the profession of tool and die maker and occasionally
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 0x9e423867bcc7d3d9c082e276784164539bf34a95692d333859081265ec2f0387. 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/61740333-1204-4175-8e52-7d39e26d57d0.json and https://artists.proofprofile.net/proofs/artist/61740333-1204-4175-8e52-7d39e26d57d0.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
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 0x02667d2027ad6113bed965a60c429e8592e474ed6ab9d69c7c4ad53e23843743. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/DEF056830101.
Le nozze di Figaro, K. 492, Act I: No. 4, La vendetta, oh, la vendetta!
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x10c46cc80a7b134a5b027109f170b3413dc759690c3982face2228626be21163. Chain 2 (Bitcoin): anchored in block 957073 (2026-07-07T18:39:05Z), 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/DEF056830105.
Le nozze di Figaro, K. 492, Act II: No. 11, Porgi amor
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x99d3c17558ae6002f7e874bf92541a74bf6250510695503e2bf95b4365304798. Chain 2 (Bitcoin): anchored in block 957075 (2026-07-07T18:50:38Z), 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/DEF056830109.
Le nozze di Figaro, K. 492, Act II: No. 12, Voi che sapete
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9abdef85adf9912748223a2c4e1a5e70b32c807391100d0aa5775ad7836117ce. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/DEF056830110.
Le nozze di Figaro, K. 492, Act III: No. 21, Sull' aria... Che soave zeffiretto "Letter Duet"
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2571e35f8bb7ddffa9fbbbdace6d7387632712a251a3e5904657b7624150fce7. Chain 2 (Bitcoin): anchored in block 953536 (2026-06-13T17:25:41Z), 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/DEF056830114.
Le nozze di Figaro, K. 492, Act IV: No. 28a, Giunse alfin il momento
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe8311c5ac35fad9d67d1d530630329757cb4c2fbd44b835415463a71239f6b43. 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/DEF056830177.
Le nozze di Figaro, K. 492, Act IV: No. 29e-g, Finale. Gente, gente, all'armi... Questo giorno di tormenti
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1cb0326f164ec3447479141e880d428d2b6c66508e3bf805045c3dc56d687c35. Chain 2 (Bitcoin): anchored in block 960166 (2026-07-29T23:39:29Z), 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEF056830118.
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