Fifteen or 15 may refer to: 15 (number), the natural number following 14 and preceding 16 one of the years 15 BC, AD 15, 1915, 2015 Music Fifteen (band), a punk rock band Albums 15 (Buckcherry
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 0xef6fd482ad27942e4e2337c4d2b2275ab309fe2f4436bcd59f39c1db40f85293. Chain 2 (Bitcoin): anchored in block 954014 (2026-06-16T22:46:20Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/356153b0-4488-4271-91dd-7f80c1a52f66.json and https://artists.proofprofile.net/proofs/artist/356153b0-4488-4271-91dd-7f80c1a52f66.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).