Soko () was a Yugoslav aircraft manufacturer based in Mostar, SR Bosnia and Herzegovina. The company was responsible for the production of many military aircraft for the Yugoslav Air Force. SOKO was
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 0xb17580126b2718062b0550436faba6e98337b2736586702a6d9ac71152c91ada. Chain 2 (Bitcoin): anchored in block 953724 (2026-06-15T01:43:13Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/8da63c26-6a03-4aeb-9398-09c598b609c6.json and https://artists.proofprofile.net/proofs/artist/8da63c26-6a03-4aeb-9398-09c598b609c6.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).