Sai Ma (, ) is one of the ten subdistricts (tambon) of Mueang Nonthaburi District, in Nonthaburi Province, Thailand. Neighbouring subdistricts are (from north clockwise) Tha It, Bang Kraso, Suan Yai (
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 0xb1448b13faaf232b387d38462c6ae50e71eb4ee172a90cc3fa2ff839f7916432. Chain 2 (Bitcoin): anchored in block 953928 (2026-06-16T10:21:55Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1d900c85-6804-4cf6-8ff6-1c41841b5b78.json and https://artists.proofprofile.net/proofs/artist/1d900c85-6804-4cf6-8ff6-1c41841b5b78.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).