Flippa is a private marketplace for buying and selling online businesses, based in Melbourne, Australia, and Austin, Texas, United States. It was founded in June 2009 by Mark Harbottle and Matt Mickie
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 0x4cf2d7b36f7a34c3216a9984096e8fe913fd267ab0a2c18a4092957e6aa6f17c. Chain 2 (Bitcoin): anchored in block 953877 (2026-06-16T02:39:16Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/01855350-a80a-4f35-bcda-a571cba1dea5.json and https://artists.proofprofile.net/proofs/artist/01855350-a80a-4f35-bcda-a571cba1dea5.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).