thumb|Territories of the Northern Wei (blue) and Liu Song (Red) states (440) Year 440 (CDXL) was a leap year starting on Monday of the Julian calendar. At the time, it was known as the Year of the C
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 0x096a30b88b81da35c4db434d4b86a191c72b70ca299c3d3ba09033788a3857dd. Chain 2 (Bitcoin): anchored in block 953875 (2026-06-16T02:12:46Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/070fb564-e93c-4005-aca6-2c65290a3520.json and https://artists.proofprofile.net/proofs/artist/070fb564-e93c-4005-aca6-2c65290a3520.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).