Dona Massin (born 18 February 1917–26 May 2001) was a film choreographer best known for her work on the 1939 film version of The Wizard of Oz. Dona Massin appeared in over 100 films throughout her ca
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 0x0f1d4bd1ddd15ac86efe7418b5e8558fb22b9ab36f2dd770b34cb0a44d72d49e. Chain 2 (Bitcoin): anchored in block 953941 (2026-06-16T11:51:19Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/20212b2d-90a4-4030-95ea-20a40fbd5b95.json and https://artists.proofprofile.net/proofs/artist/20212b2d-90a4-4030-95ea-20a40fbd5b95.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).