message: Mask zero commitments
diff: @@ -518,15 +518,9 @@ impl<G: CommitmentCurve> SRS<G> {
  .zip(blinders)
  .ok_or_else(|| CommitmentError::BlindersDontMatch(blinders.len(), com.len()))?
  .map(|(g, b)| {
  - if g.is_zero() {
  - // TODO: This leaks information when g is the identity!
  - // We should change this so that we still mask in this case
  - g
  - } else {
  let mut g_masked = self.h.mul(b);
  g_masked.add_assign_mixed(&g);
  g_masked.into_affine()
  - }
  });
  Ok(BlindedCommitment {
  commitment,
  