Duh, Duh! or DUH may refer to: Music Duh (album), 1992, by Lagwagon DUH (band), an American noise rock group Duh! (EP), 2025, by P1Harmony "Duh", 2009, by rapper Brianna Perry Other uses Mat
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 0x675938aaa6952d6dd8dde34f6e8602ca8dd0fe5bf16fc44fc0e357c6b82765cd. Chain 2 (Bitcoin): anchored in block 953928 (2026-06-16T10:21:55Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1cc78d4c-6cef-4fa5-a32b-5000edb0a281.json and https://artists.proofprofile.net/proofs/artist/1cc78d4c-6cef-4fa5-a32b-5000edb0a281.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).