AtomicSwap.vg

// Atomic Swap: (HTLC) Alice swaps a Secret for Bob's Payment.
// If Alice claims the Payment, the Secret is revealed (publicly).
// If Alice ghosts, Bob gets his money back.
// Distribution semantics: pot (20 wei) allocated based on swap outcome

game main() {
  join Alice() $ 10 Bob() $ 10;

  // Alice commits to the pre-image (the secret key)
  commit Alice(secret: int) || { Bob -> 20 };

  // Bob inspects the commitment (abstractly) and funds the contract
  yield Bob(fund: bool) || { Alice -> 20 };

  // Alice must reveal the secret to get the money
  reveal Alice(secret: int) || { Bob -> 20 };

  withdraw
      // Case 1: Bob didn't fund -> Refund everyone
      (!Bob.fund) ?
          { Alice -> 10; Bob -> 10 }
      :
      // Case 2: Bob funded, Alice revealed -> Swap happens
      // Alice gets the payment (10), Bob effectively "gets" the secret (valued at 10)
      { Alice -> 10; Bob -> 10 }
}