Sij or SIJ may refer to: Sacroiliac joint Special Immigrant Juvenile Status Siglufjordur Airport, IATA code Sij, Gilan, a village in Iran Sij, Razavi Khorasan, a village in Iran Sij, South Khor
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 0xbe10b91b52090fe33dc8225a2bb1b394b98246161f94c25de3ae15245e3b4216. Chain 2 (Bitcoin): anchored in block 953803 (2026-06-15T15:41:00Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/e0f84c14-ec47-4929-9c37-1d93c3f45971.json and https://artists.proofprofile.net/proofs/artist/e0f84c14-ec47-4929-9c37-1d93c3f45971.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).