Darder is a surname. Notable people with the surname include: Antonia Darder (born 1952), Puerto Rican academic, artist, poet, and activist Sergi Darder (born 1993), Spanish footballer See also Hard
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 0x9ae3fef48814b5a1b608a47eeda0f7cbbb2d647b6c3c943e130bdb5f04fc40fa. Chain 2 (Bitcoin): anchored in block 953923 (2026-06-16T09:51:37Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1b4e92df-379b-41e3-b587-e5a4455fac24.json and https://artists.proofprofile.net/proofs/artist/1b4e92df-379b-41e3-b587-e5a4455fac24.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).