Demo BitVM

BitVM-style boolean gate proof.

# A compact boolean proof: each bit is opened by choosing one hash from a committed pair.
Contract DemoBitVM:

    # For each wire, index 0 represents bit 0 and index 1 represents bit 1.
    Struct HashPair:
        hash0: hex
        hash1: hex

    def main(preimageE: hex, preimageB: hex, preimageA: hex):
        # Opening a preimage tells us which bit value was selected for A, B, and E.
        hA = Hash160(preimageA)
        okA = Or(Equal(hA.Clone(), self.hashPairA.hash0), Equal(hA.Clone(), self.hashPairA.hash1))
        NumEqualVerify(okA, 1)
        bitA = Equal(hA, self.hashPairA.hash1)

        hB = Hash160(preimageB)
        okB = Or(Equal(hB.Clone(), self.hashPairB.hash0), Equal(hB.Clone(), self.hashPairB.hash1))
        NumEqualVerify(okB, 1)
        bitB = Equal(hB, self.hashPairB.hash1)

        hE = Hash160(preimageE)
        okE = Or(Equal(hE.Clone(), self.hashPairE.hash0), Equal(hE.Clone(), self.hashPairE.hash1))
        NumEqualVerify(okE, 1)
        bitE = Equal(hE, self.hashPairE.hash1)

        # The selected E bit must be the NAND result of the selected A and B bits.
        EqualVerify(Not(And(bitA, bitB)), bitE)