circomlib/circuit/babyjub.circom

template BabyAdd() {
    signal input x1;
    signal input y1;
    signal input x2;
    signal input y2;
    signal output xout;
    signal output yout;

    signal beta;
    signal gamma;
    signal delta;
    signal epsilon;
    signal tau;

    var a = 168700;
    var d = 168696;

    beta <== x1*y2;
    gamma <== y1*x2;
    delta <== y1*y2;
    epsilon <== x1*x2;
    tau <== delta * epsilon;

    xout <-- (beta + gamma) / (1+ d*tau);
    (1+ d*tau) * xout === (beta + gamma);

    yout <-- (delta - a * epsilon) / (1-d*tau);
    (1-d*tau)*yout === (delta - a * epsilon);
}