thumb|Icelandic grimoire, "Galdrabók" (), belonging to Swedish History Museum (signum: ATA Ämb 2 F16:26) A grimoire (), also known as a book of spells, magic book, or a spellbook, is a textbook 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 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 0xdd626eb32772670597e02b2bce98e0d6f64a05e5c6f1ca17551a9b4d20100878. Chain 2 (Bitcoin): anchored in block 954055 (2026-06-17T05:51:24Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/435fcad0-d2ce-4a09-8855-cede14a3f0db.json and https://artists.proofprofile.net/proofs/artist/435fcad0-d2ce-4a09-8855-cede14a3f0db.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).