thumb|Esther Borja by Annemarie Heinrich, 1937 Esther Borja Lima (5 December 1913 – 28 December 2013)Given by Orovio (Orovio, Helio 1982. Diccionario de la música cubana. La Habana) as: 5 September 1
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 0xca79256668d7199791c96caa1ef735e9d7e097b507e90c87eb66cc870483ab08. Chain 2 (Bitcoin): anchored in block 954784 (2026-06-22T02:53:59Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/f6ea652c-919b-4f3c-a66f-223cede374fc.json and https://artists.proofprofile.net/proofs/artist/f6ea652c-919b-4f3c-a66f-223cede374fc.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Vintage Cuba No. 106 - EP: Rapsodia De Cuba
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 0xb7da423d2db3eca3dcb0d85ab72d123db9c5add28804228019c6949f05a5f219. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QM6N21588385.
Canciones inolvidables de Ernestina Lecuona (Remastered)
Esther Borja interpreta a Ernesto Lecuona (Remasterizado)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd0b01f95dfeacea458cf0011d193d15f67750d502348de9bbd826ed9df145d41. Chain 2 (Bitcoin): anchored in block 960203 (2026-07-30T03:35:13Z), 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/USV351428750.