thumb|right|260px|Large sahn of the Great Mosque of Kairouan, surrounded by riwaq (arcades), in Tunisia. A sahn (, ), is a courtyard in Islamic architecture, especially the formal courtyard of a mosq
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbdb0eb6d21e3ce38f16b1827f91df1a514654e3ac625a26de55a98ca4ed666cc. Chain 2 (Bitcoin): anchored in block 954623 (2026-06-20T23:40:06Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/cb3bdc18-19d9-4afe-b41e-bd7d03a5dafd.json and https://artists.proofprofile.net/proofs/artist/cb3bdc18-19d9-4afe-b41e-bd7d03a5dafd.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).