Abraham Brumberg (; November 7, 1926 – January 26, 2008) was an American writer and editor. He wrote about the Soviet Union, Eastern Europe, and Jewish issues. He was the first editor of Problems of
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc3fd764af9a9f62cbc91891fa79e5e7b41b2c7b728bb5ae1e7d9a2b3bba2cd93. Chain 2 (Bitcoin): anchored in block 953907 (2026-06-16T07:39:24Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/17a8258a-c53c-4091-a1dd-d8820863a983.json and https://artists.proofprofile.net/proofs/artist/17a8258a-c53c-4091-a1dd-d8820863a983.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).