Keystone or key-stone may refer to: Keystone (architecture), a central stone or other piece at the apex of an arch or vault Keystone (cask), a fitting used in ale casks Companies Keystone Law, a f
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 0xf1fa6ac4f6e0d77ba43bf8fecc57717fe1f0ef3af4d96132bb59520d6063a8b0. Chain 2 (Bitcoin): anchored in block 954631 (2026-06-21T02:46:24Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/d08cf548-e040-46ba-ab1f-0298e6c0fa23.json and https://artists.proofprofile.net/proofs/artist/d08cf548-e040-46ba-ab1f-0298e6c0fa23.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).