20XX is a platform game developed by American studio Batterystaple Games. The early access version was released for Microsoft Windows on Steam on October 12, 2016, and in full on August 16, 2017. Play
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 0xac759b4bb1138338874557b085bff1ef9c07e408c9bd08ee4b3004934c5541a9. Chain 2 (Bitcoin): anchored in block 953871 (2026-06-16T01:46:03Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/0768f819-fd29-4735-9765-8043b5a787c2.json and https://artists.proofprofile.net/proofs/artist/0768f819-fd29-4735-9765-8043b5a787c2.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.