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 0x2397d4cc5ee071c64657dbe57641faca6dffbf25e37371834a51675056cd205d. Chain 2 (Bitcoin): anchored in block 953759 (2026-06-15T08:04:42Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/b654527d-216d-466f-964e-252ece8c462e.json and https://artists.proofprofile.net/proofs/artist/b654527d-216d-466f-964e-252ece8c462e.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Vocal Music (16Th Century Spanish) - Brudieu, J. / Fletxa, M. / Alberch, P. (Madrigals and Ensaladas From 16Th Century Catalonia) (La Colombina)
Vocal Ensemble - Encina, J. / Guerrero, F. / Encina, J. / Vasquez, J. / Romero, M. (Canciones, Romances, Sonetos) (La Colombina)
Christmas In Spain And The Americas In The 16Th Century (La Colombina)
Choral Music (16Th Century Renaissance) - Victoria, T.L. / Pujol, J.P. (La Colombina)
Vocal Music - Romero, M. / Blas De Castro, J. / Diaz, G. / Pujol, J.P. / Rios, A. (Music in the Spain of Philip Iv) (La Colombina)
Vocal Music (Extracts From the Maundy Thursday Liturgy in Spain and Its Dominions) (La Colombina)
Tomás Luis de Victoria: Officium Hebdomadae Sanctae