message: Make ivk pub
diff: @@ -84,7 +84,7 @@ impl<E: JubjubEngine> ViewingKey<E> {
  )
  }
  - fn ivk(&self) -> E::Fs {
  + pub fn ivk(&self) -> E::Fs {
  let mut preimage = [0; 64];
  self.ak.write(&mut preimage[0..32]).unwrap();
  