Johann Vierdanck (also Virdanck, Vyrdanck, Feyertagk, Feyerdank, Fierdanck; ca. 1605–1646) was a German violinist, cornettist, and composer of the Baroque period. Life Vierdanck was born near Dresd
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 0xf60b63ac37e94b138e03003c3dde754357cd9f0f30bc32fbac724e8ab1d111dd. Chain 2 (Bitcoin): anchored in block 954342 (2026-06-19T03:22:39Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/904f2c0b-1de4-43bd-ad3c-56303c83c5b3.json and https://artists.proofprofile.net/proofs/artist/904f2c0b-1de4-43bd-ad3c-56303c83c5b3.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Chamber Music: London Baroque - Rosenmuller, J. / Hacquart, C. / Buxtehude, D. / Biber, H. I. F. (The Trio Sonata in 17Th Century Germany)
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 0x0507340c272b5da3983470de1136074638f42287a88d6468d681e1f924accb8e. Chain 2 (Bitcoin): anchored in block 956312 (2026-07-02T05:09:12Z), 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/SEAEP0845010.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x40070607a61d85135b2ed5f2eb9a7a2ae1ef8e32112ce83697044aabe111c317. 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/SEAEP0845020.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcb4a786ed8b9b4d51ae593231707f606c1ad453ffbf0112d82f8aff39160f64a. 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/SEAEP0845030.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x31f73a80cb502f60d0df768ec8fae0f66db856f430f57774f026298910260459. 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/BEE021602307.
Rappresentatione di Anima, et di Corpo, Atto secondo, Intermedio: Capriccio
Cavalieri: Rappresentatione di Anima, et di Corpo
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x18c5c3343ad44c40d67f93f6a24acf3824a45ea91bf92721f2c2ef3b6344b3d2. 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/FR50X0406517.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6398361e433f810b614e5c306ee32f7d356548de95561574271e6d0b22e350c8. Chain 2 (Bitcoin): anchored in block 960229 (2026-07-30T08:30:10Z), 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/SEAEP0845040.
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