Gacek (Polish: ) is a male domestic cat with tuxedo fur. Between 2020 and 2023, this homeless cat was a tourist attraction in Szczecin, Poland. In 2020, a video of Gacek was distributed around the wor
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 0x939d4afb383266bcfe218cd1afa8b73ce2fbf50ac3f13d364f9b08a28172838e. Chain 2 (Bitcoin): anchored in block 953909 (2026-06-16T07:53:13Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/0b9a1243-f6d4-4fb4-9c5e-abfcd642adcf.json and https://artists.proofprofile.net/proofs/artist/0b9a1243-f6d4-4fb4-9c5e-abfcd642adcf.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).