Gudrun Schröfel (born 1 February 1943) is a German choral conductor, conductor and academic teacher. She led choirs, namely the Mädchenchor Hannover, to competition successes and awards for recordings
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 0x7c00e45f6c73627d501b54ad52664801e365943c53e5d23ca408871c909d2646. 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/59b9e775-c086-42f0-8874-47fe9651578d.json and https://artists.proofprofile.net/proofs/artist/59b9e775-c086-42f0-8874-47fe9651578d.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Andreas Tarkmann: Inka-Kantate Töchter der Sonne & Gustav Holst: Savitri
Sacred Vocal Music from Wolfenbüttel (Verklingend und ewig)
Il secondo Libro de Madrigali a quattro voci (Das zweite Madrigalbuch): No. 5 o notte, o ciel', o mar', o piaggie, o monti!
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 0x0d9effe221932c9361fc92603a9bc6a0d3276ed110ff47d1cda09ac9b3b27a98. 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/DEN421111005.
Maria Xaveria Perucona & Chiara Margarita Cozzolani: Psalmen und Motetten aus italienischen Konventen (Gaude, Plaude!)
Benjamin Britten: Children's Crusade / A Ceremony of Carols
A Ceremony of Carols, Op. 28 No. 1-12: No. 5 Balulalow
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf46d28668fa621821c30f727e4652e4443bd38a83676607adecbc1243c829291. 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/DEN421504005.
Andreas N. Tarkmann: Didos Geheimnis (Dido's secret)
Glaubenslieder: Neue Kantaten zum Kirchenjahr
Choral Hymns From The Rig Vega: III. Hymn To Vena
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6790235233d54c05fd94696bab170515aabc8ea9003929e40108b426dd130e69. 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/DEC299217410.
Jakobs Stern ist aufgegangen. Weihnachtliche Chormusik
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x59d6ce6a8ef26dad6acba0916292ffc8891ba1a7eb59e855280602a51e9d3e6e. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEB119200112.
Weihnachtliche Chormusik der Romantik (Arr. von Andreas N. Tarkmann)
Weihnachten - Stille, stille, lasst uns lauschen