Bluff in public. Prove in private.

Card games where every round is proven fair.

Proof or Bluff is a pair of bluffing card games rebuilt for the Midnight Network. You and a talkative computer opponent hold private cards and make public claims about them — truthful or not. When someone calls "Proof or Bluff!", a zero-knowledge proof settles it on-chain, revealing only whether the claim was true.

Play — pick your table Read the rules

Free to play, right now — live on Midnight Mainnet. The house sponsors every game: no wallet, no tokens, no cost to you.

Proof or Bluff banner art: playing cards on a dark purple table.

Two tables, one promise

Pick your game. Both are free, wallet-free, and proven on Midnight Mainnet round by round.

The classic

Original

Based on "Cheat": seven private cards each from one shared deck, play face down, claim the required rank, and bluff your way out. Empty your hand to win — unless you're caught at the door. Catch bluffs for +3, race to 15.

7 cards · empty-hand or points win · 3–10 min

Play Original

New · quick-fire

5 Up 2 Down

Two cards down for you, five face up for everyone. Claim how many of yours match the board — the house accepts or calls "Proof or Bluff!". Honest claims pay; proven claims pay double; every lie costs you a point and hands it over. Race to 20.

2 + 5 cards · race to 20 · 2–5 min

Play 5 Up 2 Down

How privacy works

You never need to understand zero-knowledge proofs to play. But if you are curious, here is what the game actually guarantees, in plain English.

Your cards stay private

Your hand is committed on-chain, not published. The public chain holds only commitments — cryptographic fingerprints — of your hand, your plays, and the shuffle seed. Your opponent never sees your cards, and the chain itself never learns them.

Every round is proven, not promised

After each round a zero-knowledge proof lands on Midnight showing that every card played — yours and the computer's — was actually dealt, every challenge was ruled by the rules, and the score follows. Play a card you were not dealt and the proof simply fails; the transaction can never confirm. When a game ends, its full transcript is published so anyone can re-run the rules and check the on-chain result for themselves.

The chain only learns true or false

When a claim is challenged, the contract checks the hidden cards against the public claim and discloses exactly one thing: whether it was honest — or, in 5 Up 2 Down, how many of the claimed cards were lies. It does not reveal what the cards were, and it reveals nothing about the rest of either hand.

An honest note about proving. When you use our hosted proof server, that server processes your private cards while generating your proof. Advanced players can run their own proof server for full privacy. The game's fairness is enforced by the contract either way — this choice only decides who can see. Read the full privacy and trust model.

A round in thirty seconds (Original)

Deal. Both sides commit random entropy, the shared seed is revealed, and each hand is dealt from it inside the proof. Nobody chose the cards.
Play and claim. On your turn, play one to four cards face down and declare the current required rank — "Two Kings". The cards can be anything.
Accept or challenge. Your opponent either accepts (the pile grows, the rank advances) or calls "Proof or Bluff!".
Resolve. A zero-knowledge proof reveals whether the claim was true. The pile is discarded and points are awarded. First to the mode's target score wins.

Full rules, modes, and scoring · 5 Up 2 Down rules

Ready to call a bluff?

Sit down with the computer opponent and feel selective privacy for yourself.

Play Original Play 5 Up 2 Down