Marcin Krzysztof Urbaś (born September 17, 1976) is a former Polish track and field athlete. He is the Polish record holder for the 200 metres dash with 19.98 seconds. He is now a sprinting coach. Tr
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 0xbb138ce151f297df2f8f1d6b449e30528e984cc296cbd0f48fb6a45147ea0684. Chain 2 (Bitcoin): anchored in block 953697 (2026-06-14T21:49:28Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/6b8221e4-4351-4947-84bc-cf53ab6d59bd.json and https://artists.proofprofile.net/proofs/artist/6b8221e4-4351-4947-84bc-cf53ab6d59bd.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.