Whist is a classic English trick-taking card game that was widely played in the 18th and 19th centuries.Waddingtons Family Card Games, Robert Harbin, Pan Books Ltd, London, 1972 Although the rules are
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 0xa2877af1117b8df8a5920c5f3882d62ea78305311db4f3fed9fd5b546c75f8eb. Chain 2 (Bitcoin): anchored in block 954659 (2026-06-21T06:14:42Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/dbd03bd5-c487-40f1-afae-09a130380834.json and https://artists.proofprofile.net/proofs/artist/dbd03bd5-c487-40f1-afae-09a130380834.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).