thumb|Portrait of Antonín Kraft Antonín Kraft (30 December 1749 – 28 August 1820) was a Czech cellist and composer. He was a close friend of Haydn, Mozart, and Beethoven. He worked in the Holy Roman
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 0x1c999536567c7b585f7e543147b3df1d03f7bd8d23d54bdad1b52fd8c2060026. Chain 2 (Bitcoin): anchored in block 954631 (2026-06-21T02:46:24Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/d2c30d5d-70d2-4400-8479-5dcd38aaa7cf.json and https://artists.proofprofile.net/proofs/artist/d2c30d5d-70d2-4400-8479-5dcd38aaa7cf.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Cello Concerto in C Major, Op. 4: I. Allegro aperto
Antonín Kraft, Carl Philipp Emanuel Bach: Cello Concertos
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 0xd99b38725850ad886b9333631d369b299f1c50fabb75c365bce3d6e3b1dd100c. Chain 2 (Bitcoin): anchored in block 957073 (2026-07-07T18:39:05Z), 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/FR7JM2386010.
Cello Concerto in C Major, Op. 4: II. Romance. Andante
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc1216b1ef8d8e7beb40274d3a34ac9f947e69ffab26736457088494c733cb52e. Chain 2 (Bitcoin): anchored in block 960138 (2026-07-29T19:35:34Z), 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/FR7JM2386020.
Cello Concerto in C Major, Op. 4: III. Rondo alla Cosacca. Moderato
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdd175b6a2fb11a5e5b63f71132f2e8aabedd121271dbaf729b361da8c526dca9. Chain 2 (Bitcoin): anchored in block 960138 (2026-07-29T19:35:34Z), 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/FR7JM2386030.