ZETHProvably unlinkable.

pragma circom 2.1.6;

include "poseidon.circom";
include "bitify.circom";

// Note commitment: cm = H(value || pk || rho)
template Commitment() {
    signal input value;
    signal input pk;
    signal input rho;
    signal output cm;
    component h = Poseidon(3);
    h.inputs[0] <== value;
    h.inputs[1] <== pk;
    h.inputs[2] <== rho;
    cm <== h.out;
}

// Nullifier: nf = H(cm || sk)
template Nullifier() {
    signal input cm;
    signal input sk;
    signal output nf;
    component h = Poseidon(2);
    h.inputs[0] <== cm;
    h.inputs[1] <== sk;
    nf <== h.out;
}

// Merkle membership against the accumulator root
template MerklePath(depth) {
    signal input leaf;
    signal input pathElements[depth];
    signal input pathIndex[depth];
    signal output root;
    component hash[depth];
    signal cur[depth + 1];
    cur[0] <== leaf;
    for (var i = 0; i < depth; i++) {
        pathIndex[i] * (1 - pathIndex[i]) === 0;
        hash[i] = Poseidon(2);
        hash[i].inputs[0] <== pathIndex[i] == 0 ? cur[i] : pathElements[i];
        hash[i].inputs[1] <== pathIndex[i] == 0 ? pathElements[i] : cur[i];
        cur[i + 1] <== hash[i].out;
    }
    root <== cur[depth];
}