thumb|A typical SIM card (mini-SIM with micro-SIM cutout)A SIM card or SIM (subscriber identity module) is a type of integrated circuit, often in the form of a smart card. They are intended to securel
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 0x2f23b4e80bd0bc0f1dbe8b983b19920d02f56fbe594d19ef56a26b3a991b83f8. Chain 2 (Bitcoin): anchored in block 953694 (2026-06-14T21:38:09Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/6c3e9517-04d0-4213-b70c-335b395fe5b6.json and https://artists.proofprofile.net/proofs/artist/6c3e9517-04d0-4213-b70c-335b395fe5b6.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).