thumb|Detail of Landini wearing a corona laurea while playing an organetto in an illustration from the 15th-century Squarcialupi Codex I-Fl 87, f. 121v Francesco Landini ( or 1335 – 2 September 1397;
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 0xc0f5890124cadcb8de8658bf857ec5437f4b5b6e3b28a6b228feef8892e1c331. 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/205ce16a-6217-4a13-9427-446b0079424d.json and https://artists.proofprofile.net/proofs/artist/205ce16a-6217-4a13-9427-446b0079424d.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
I am Music - The Music of the 14th Century Vol. 3
The Second Circle - Love Songs of Francesco Landini
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 0x74cff6de38824d9db48524ee8674ec2a85f5e7bc5806b258292f22a59003b9dd. Chain 2 (Bitcoin): anchored in block 958491 (2026-07-18T04:29:42Z), 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/USHM10026902.
Francesco Landini: Trecento (Arr. for Guitar)
Francesco Landini: Angelica biltà (Arr. for Guitar)
Brian Gulland/David White/Robin Jeffrey/Peter Lockett/Hughes de Courson
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x179451fe5910596736d37fe07d344ee246016da3b5365223a754aaa320d0e0b8. Chain 2 (Bitcoin): anchored in block 957124 (2026-07-08T03:53:27Z), 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/FR34F0300030.
Echo la primavera (Italian Ars Nova): Echo la primavera
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x87a152204e02a27d90708aff8681dca0d6d178a24e5fc4fd78d1709961c0bd90. Chain 2 (Bitcoin): anchored in block 960448 (2026-07-31T18:48:12Z), 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/USHM10026901.
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