DOS-2 was a space station, launched as part of the Salyut programme, which was lost in a launch failure on 29 July 1972, when the failure of the second stage of its Proton-K launch vehicle prevented t
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 0xb8e56b2140f9983a2c1b15e764e05c57d23191364eda32239db0c4e749eba467. Chain 2 (Bitcoin): anchored in block 954705 (2026-06-21T13:42:37Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/efc1c542-d347-4d35-b5d3-cc95423286cc.json and https://artists.proofprofile.net/proofs/artist/efc1c542-d347-4d35-b5d3-cc95423286cc.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).