Contraband (from Medieval French contrebande "smuggling") is any item that, relating to its nature, is illegal to be possessed or sold. It comprises goods that by their nature are considered too dange
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 0x6891bb480a77f33d7ed80b355d4adbaad242587bf0d458245b1e3ef17380c42f. Chain 2 (Bitcoin): anchored in block 954066 (2026-06-17T08:11:48Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/76b71d94-443a-4ccf-aa6f-273e7655eca2.json and https://artists.proofprofile.net/proofs/artist/76b71d94-443a-4ccf-aa6f-273e7655eca2.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).