thumb|Labor () Josef Paul Labor (29 June 184226 April 1924) was an Austrian pianist, organist, and composer of the late Romantic era. Labor was an influential music teacher. As a friend of some key fi
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 0x375ebac00ba9ea78997b50e909cffe9269f5cc731ad1edf9bc03fc25a2e10edf. Chain 2 (Bitcoin): anchored in block 954728 (2026-06-21T18:08:38Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/fcc52d95-9492-4310-8c74-c17fb92ffc63.json and https://artists.proofprofile.net/proofs/artist/fcc52d95-9492-4310-8c74-c17fb92ffc63.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
The Organ Works of Josef Labor (1842-1924) : The Organ of St. Ignatius, Stamford Hill, London
Labor: Piano Quintet in E Minor, Op. 3 & Piano Quartet in C Major, Op. 6
Labor: Clarinet Trio & Cello Sonata No. 2
Labor: Piano Concertos for the Left Hand Nos. 1-3
Piano Concerto for the Left Hand No. 1: III. Var. 3
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 0xf0c0bbb8bf109ee4fa007b41f98ff8dc5bdc23dd8b12a13904c63204a7e5d81c. Chain 2 (Bitcoin): anchored in block 956349 (2026-07-02T11:34:59Z), 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/DEB262300233.
Piano Concerto for the Left Hand No. 2: III. Finale
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3413935cc788c56296d75656f1e9a051e5d1ad89e728de51b6ac2f4dfe66f76f. Chain 2 (Bitcoin): anchored in block 956302 (2026-07-02T03:30:09Z), 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/DEB262300238.
Piano Concerto for the Left Hand No. 1: I. Introduktion - Thema
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x83bc01249bd713b21b21274b187dd6f3e069d1b618522a26ada8fcf415a13378. Chain 2 (Bitcoin): anchored in block 960459 (2026-07-31T20:22:46Z), 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/DEB262300231.
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