thumb|400px|Buda in the Middle Ages (Nuremberg Chronicle, 1493) Buda (, ), Czech and , is the part of Budapest, the capital city of Hungary, that lies on the western bank of the Danube. Historically
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 0xd10566241cc3b53e1024cfe34a11246687a85403cbb9ea3c3f68b97fbe1d2306. Chain 2 (Bitcoin): anchored in block 954342 (2026-06-19T03:22:39Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/8d8453cb-a38d-4f83-a9ad-c7304b176fb0.json and https://artists.proofprofile.net/proofs/artist/8d8453cb-a38d-4f83-a9ad-c7304b176fb0.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).