thumb|upright=1.1|A postcard of the rhyme using Dorothy M. Wheeler's 1916 illustration "Jack and Jill" (sometimes "Jack and Gill", particularly in earlier versions) is a traditional English nursery
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 0xae050bf8e351dca9fdc7acc602acdfd2d38dcec781c275047554a01dbba690da. Chain 2 (Bitcoin): anchored in block 954603 (2026-06-20T21:47:54Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/c3aaa16a-0035-4f89-b3c4-568ba997a324.json and https://artists.proofprofile.net/proofs/artist/c3aaa16a-0035-4f89-b3c4-568ba997a324.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).