The Vermeer Quartet was a string quartet founded in 1969 at the Marlboro Music Festival in Vermont and active until 2007. Background They performed in North and South America, Europe, the Far East, a
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 0x53d3c55bdabc1f093f76cfa93d991d8385dab77d23c40e30a4f2fb449b5f29dd. 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/693463b7-5365-4ecf-96e9-4d8c3dff54fe.json and https://artists.proofprofile.net/proofs/artist/693463b7-5365-4ecf-96e9-4d8c3dff54fe.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Bliss: Oboe Quintet / Britten: Phantasy / String Quartet No. 3
Vermeer Quartet - Death and the Maiden: Schubert, Beethoven, Dvořák, Mendelssohn
Schubert: String Quartet No. 14 in D Minor, D. 810 "Death and the Maiden": III. Scherzo. Allegro molto - Trio
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 0xca4ae673cf8bd2c11c2319c04e7f8adf1bfb28aab60eda9c8116d19a5c418953. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), 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/DEA808301903.
Dvořák: String Quartet No. 12 in F Major, Op. 96, B. 179 "American": III. Molto vivace
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xeb58c7f140ed3d7656612ee26c37fbaac1629b4a62b34694cd42559a1879aa09. Chain 2 (Bitcoin): anchored in block 958880 (2026-07-20T15:04:01Z), 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/DEA802400118.