thumb|270px|A German journalist eating a portion of skyr in 1934 thumb|Mass-produced vanilla skyr thumb|Varieties of flavored skyr Skyr ( ; ) is a traditional Icelandic cultured dairy product. It has
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 0xdf11b1e782432354a93f8658f9b824a6ecd8a80ed642c7ff53cca55671def6df. Chain 2 (Bitcoin): anchored in block 954027 (2026-06-17T00:55:08Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/39a827ab-81db-412b-8e18-2c7aeba91040.json and https://artists.proofprofile.net/proofs/artist/39a827ab-81db-412b-8e18-2c7aeba91040.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).