Maroua (Fula: Marwa, , 𞤥𞤢𞤪𞤱𞤢) is the capital of the Far North Region of Cameroon, stretching along the banks of the Ferngo and Kaliao Rivers, in the foothills of the Mandara Mountains. The city had 20
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 0xb8803f523b77f755694a2452de67c123957d94ef1faa4acae41bb91c8ac769bd. Chain 2 (Bitcoin): anchored in block 954647 (2026-06-21T04:36:58Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/d6547688-ae76-49a2-868c-933c873daf99.json and https://artists.proofprofile.net/proofs/artist/d6547688-ae76-49a2-868c-933c873daf99.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).