Birkhoff is a surname. Notable people with the surname include: George David Birkhoff (1884–1944), American mathematician Garrett Birkhoff (1911–1996), American mathematician, son of George D. See a
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 0x3e834bac04769bb877e11831e3c8760fb4a53c1d0b563bf5a98a3ac51c4f0e8a. Chain 2 (Bitcoin): anchored in block 954342 (2026-06-19T03:22:39Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/859f61a1-af91-44ec-9d4d-b11f2a2f24e6.json and https://artists.proofprofile.net/proofs/artist/859f61a1-af91-44ec-9d4d-b11f2a2f24e6.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).