John Marsh may refer to: Politicians John Marsh (MP fl. 1394–1397), MP for Bath John Marsh (MP fl. 1414–1421), MP for Bath John Allmond Marsh (1894–1952), Canadian Member of Parliament John Otho Mars
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 0x40ebaa60694ac8a5c8009a9150f43c1365310262dcc337cbb8e68ec96327421f. Chain 2 (Bitcoin): anchored in block 954659 (2026-06-21T06:14:42Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/dcf98c24-3cfc-4e75-a49c-28dff8ff7725.json and https://artists.proofprofile.net/proofs/artist/dcf98c24-3cfc-4e75-a49c-28dff8ff7725.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Marsh: Symphonies Nos. 2, 6, 7, 8 / Conversation Symphony for 2 Orchestras
Marsh Voluntary 8 in C Minor/Major Set 4