The Cassi were a tribe of Iron Age Britain in the first century BCE. They are known only from a brief mention in the writings of Julius Caesar.Julius Caesar, Commentarii de Bello Gallico 5.21 They may
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 0x43d6459153145149b2fee975b29e95051c3ffeb40aa3041e7fbbc25b5e92a3ff. Chain 2 (Bitcoin): anchored in block 954017 (2026-06-16T23:38:33Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/3779c746-10c7-4c50-a81d-aedd6757d4d4.json and https://artists.proofprofile.net/proofs/artist/3779c746-10c7-4c50-a81d-aedd6757d4d4.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).