Roberto Alfonso Calero Piedrahita (January 1, 1943 – April 4, 2021) was an Ecuadorian bolero singer. Biography He was born in 1943 in Vinces, Los Ríos Province. He started his musical career when he
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 0x8e94746b6f3d82d1e01eb76a29405a471911c617b54c98e9541f7053ea54ebc8. Chain 2 (Bitcoin): anchored in block 953727 (2026-06-15T02:33:01Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/90286dab-9556-490e-aac2-564e209795fe.json and https://artists.proofprofile.net/proofs/artist/90286dab-9556-490e-aac2-564e209795fe.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.