Porto, officially the Ancient, Very Noble, Ever Loyal and Undefeated City of Porto, also known in English as Oporto, is the second largest city in Portugal, after Lisbon. It is the capital of the Port
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 0xdaeb4714868542949d3a80e5f17a57d045dbb7f8993f90f4554c24a16b160b64. Chain 2 (Bitcoin): anchored in block 953973 (2026-06-16T16:37:07Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/2a43a1cb-e514-453d-b82a-03f5264bbe19.json and https://artists.proofprofile.net/proofs/artist/2a43a1cb-e514-453d-b82a-03f5264bbe19.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.