Gruff may refer to: Gruff, harsh and surly in nature and/or tone of voice Gruffs, servants of the Summer Faerie Court in Jim Butcher's The Dresden Files series The Three Billy Goats Gruff, Norwegian
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 0xbd4b7b4af8011496b9421b546f6d7f4ae213b7aff3ca40066905a0dbc803f999. Chain 2 (Bitcoin): anchored in block 954650 (2026-06-21T04:51:12Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/da6517ed-5d42-42f8-a160-3c6b48d15200.json and https://artists.proofprofile.net/proofs/artist/da6517ed-5d42-42f8-a160-3c6b48d15200.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).