Mercader is a Catalan family name. It may refer to: Caridad Mercader (1892–1975), Spanish communist militant and Soviet agent Maria Mercader (1965–2020), American journalist and news producer María M
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 0xd0cf99d03e6f53224d8ce091c9d583216770b1ec264d9f2c6c5dd76f6f944815. Chain 2 (Bitcoin): anchored in block 953786 (2026-06-15T12:56:12Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/daefb6f2-3371-4b37-8672-38ecc4a0db9d.json and https://artists.proofprofile.net/proofs/artist/daefb6f2-3371-4b37-8672-38ecc4a0db9d.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).