However if you get hold on a single copy, you're not willing to publish it, as it will point to you as the source of the leak. You also can't get access to anot

However if you get hold on a single copy, you're not willing to publish it, as it will point to you as the source of the leak. You also can't get access to another copy, because the person that got that, has the same consideration. So you need someone who has an access to two copies, or is trusted, by at least two people with copies, to remove hidden data.