public boolean isValid() {
Element t0, t1;
if (infFlag != 0) return true;
t0 = field.getTargetField().newElement();
t1 = field.getTargetField().newElement();
t0.set(x).square().add(getField().getA()).mul(x).add(getField().getB());
t1.set(y).square();
return t0.isEqual(t1);
}
protected final void pointToAffine(Element Vx, Element Vy, Element z, Element z2, Element e0) {
// Vx = Vx * z^-2
Vx.mul(e0.set(z.invert()).square());
// Vy = Vy * z^-3
Vy.mul(e0.mul(z));
z.setToOne();
z2.setToOne();
}
public CurveElement<?> setFromHash(byte[] source, int offset, int length) {
infFlag = 0;
x.setFromHash(source, offset, length);
Element t = field.getTargetField().newElement();
for (; ; ) {
t.set(x).square().add(curveField.a).mul(x).add(curveField.b);
if (t.isSqr()) break;
x.square().add(t.setToOne());
}
y.set(t).sqrt();
if (y.sign() < 0) y.negate();
if (curveField.cofac != null) mul(curveField.cofac);
return this;
}