thumb|De Leeuw at the Holland Festival 1976 at the Concertgebouw in Amsterdam Lambertus Reiner "Reinbert" de Leeuw (8 September 1938 – 14 February 2020) was a Dutch conductor, pianist and composer. L
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 0xe02dbb32fb96e3010113fce35bd46faeb92f6993a2d20e6e015f225465b25124. Chain 2 (Bitcoin): anchored in block 953407 (2026-06-12T19:24:56Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/a80d0883-3e57-4bc2-bb96-7b8e9957bf7c.json and https://artists.proofprofile.net/proofs/artist/a80d0883-3e57-4bc2-bb96-7b8e9957bf7c.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
Martin: Die Weise von Liebe und Tod des Cornets Christoph Rilke
Ligeti : Project Vol.1 - Melodien, Chamber Concerto, Piano Concerto & Mysteries of the Macabre
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 0x1709827078c3ba14bd29c68ab3335fcec4971e4011c379ea1bf16c59d40637e1. 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/DEA800102300 — a six-check JSON result.
Ligeti: Piano Concerto: I. Vivace molto ritmico e preciso
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb604b5bb1e6b2db7a9ef111164074ae17208d66a430d37c1fdc750e34e933860. 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/DEA800102501 — a six-check JSON result.
Metamorphosis (Classical Meets Jazz and Modern)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0bdd0c3999758968f06c481f61d43bfb58e1f5d06d330c736ccfa934c416b7f2. 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/DEA291500073 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6aca639ccd4460523f04a7f230ba5b1c5f7a595aad6f81972769fa46362f4659. 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/USNO19429501 — a six-check JSON result.
Ruth Crawford Seeger: Music for Small Orchestra; Study in Mixed Accents; Three Songs; Three Chants; String Quartet; Two Ricercari; Andante for String Orchestra; Rissolty Rossolty; Suite for W
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x08044852544f9dd16ba5aad2e59161190605cf63ded3f091240475f6fac2b8f3. 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/DEF059604400 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc6212c01a9c6405c8cdecb864447af6b4e3575256dd824070e6454752a36b69b. Chain 2 (Bitcoin): anchored in block 960410 (2026-07-31T13:50:38Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USNO19429502 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf163d138cd6e0f6bed4b272f98dc23b75828713c75bb2731bc2681919ea1d30c. 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/USNO19429503 — a six-check JSON result.