AZF may refer to: AZF (factory) (French initialism for AZote Fertilisant, i.e. nitrogen fertiliser) AZF (terrorist group) believed to have taken its name from an explosion at the AZf factory in Toul
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 0x8f8fa843246f6347825cf1dea7203b7e3f244ee3f43fde3c75d2e4f22bb8214b. Chain 2 (Bitcoin): anchored in block 954058 (2026-06-17T06:34:31Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/44d67616-4117-4f56-bdc2-6049dfa648c6.json and https://artists.proofprofile.net/proofs/artist/44d67616-4117-4f56-bdc2-6049dfa648c6.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).