NOTIS (Northwestern Online Total Integrated System) was a seminal integrated library system first created at Northwestern University, Evanston, IL USA in 1968. John P. McGowan, University Librarian fr
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 0x0ea74bdb399d2a0624f0e1dbb4f17a07159d2c73f99a4c3e322a5c32089c3740. Chain 2 (Bitcoin): anchored in block 953888 (2026-06-16T04:55:23Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/0e0e48e6-0998-4c7e-a1f0-6ab573f81706.json and https://artists.proofprofile.net/proofs/artist/0e0e48e6-0998-4c7e-a1f0-6ab573f81706.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).