The Marmen Quartet is a string quartet based in the UK, with violinists Johannes Marmen and Laia Valentin Braun, violist Bryony Gibson-Cornish and cellist Sinéad O'Halloran. The quartet was founded i
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x522bda12d0990cedf75e496325a601e949d153315d924db0742218985ee00820. Chain 2 (Bitcoin): anchored in block 954667 (2026-06-21T07:29:20Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/c188c441-b9e2-4b52-a7f9-fad48880db6e.json and https://artists.proofprofile.net/proofs/artist/c188c441-b9e2-4b52-a7f9-fad48880db6e.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).