Marsa may refer to: Places Marsa, Aude, a commune in the Aude department of France Marsa, Malta, a city in central Malta Mârșa, a commune in Giurgiu County, Romania La Marsa, a suburb of the city 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 0x36f797939b28dff9f48118612a422f2cfa6494fc1c4ea835fdb6187c5f845b2f. Chain 2 (Bitcoin): anchored in block 954533 (2026-06-20T08:57:02Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/a52f17d7-0eed-4fbb-a5da-ddc4b4dd1804.json and https://artists.proofprofile.net/proofs/artist/a52f17d7-0eed-4fbb-a5da-ddc4b4dd1804.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).