thumb|An elderly Bengali man in Dhaka with a beard dyed in henna Henna is a dye made from dried, powdered leaves of Lawsonia inermis, producing reddish stains used in body art. It has been used since
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 0x119f5f4a5ef7bd04c80dd1e78ff432d2f358357b4301c04c078fec7e4b40f8f8. Chain 2 (Bitcoin): anchored in block 953654 (2026-06-14T16:26:51Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/487114e5-ad30-4d3a-9b23-c4e2a5448d84.json and https://artists.proofprofile.net/proofs/artist/487114e5-ad30-4d3a-9b23-c4e2a5448d84.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.