C9, C09 or C-9 may refer to: Biology, medicine, and chemistry C9 (Complement component 9), a protein ATC code C09, a subgroup of the Anatomical Therapeutic Chemical Classification System C09, ICD-
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 0x60cc68553e01c1cccf0e87244437c7d7102803a416dcd294b648c0db31140a95. Chain 2 (Bitcoin): anchored in block 953958 (2026-06-16T14:52:44Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/26bfe618-1836-4a88-a6c4-918857f41bed.json and https://artists.proofprofile.net/proofs/artist/26bfe618-1836-4a88-a6c4-918857f41bed.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).