The Group of Experts on Action against Trafficking in Human Beings, more commonly known as GRETA, is the monitoring mechanism on human trafficking established by the Council of Europe Convention on Ac
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 0x484ef18a67a661c32e3fe1bdf7f19a851cc2c9d6861951820d17226321847672. Chain 2 (Bitcoin): anchored in block 953949 (2026-06-16T13:28:01Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/13c822a0-bf61-4807-ada9-f180367142b6.json and https://artists.proofprofile.net/proofs/artist/13c822a0-bf61-4807-ada9-f180367142b6.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).