&gt;In the physical example, according to the FBI&#x27;s &quot;just this one iPhone&quot; claim, one would reasonably expect that the company could then destroy the hypothetical master key as soon as it&#x27;s used. This makes sense in a physical world, but the analogy breaks down completely in a digital world.<p>Why not? Can&#x27;t apple just delete it?<p>&gt;In the digital world, you can&#x27;t guarantee that the key hasn&#x27;t been copied, and you can&#x27;t guarantee that destroying the &quot;original instance&quot; of the key destroys all others.<p>You can&#x27;t do that in the physical world either. But you can be pretty damn certain that it isn&#x27;t done.<p>&gt;The custom OS that the FBI is asking Apple to build will also take development time, and likely take more than one person to develop, meaning that if there&#x27;s a security breach during the OS&#x27;s development, any number of intermediate builds may also be stolen during development, before the FBI can even access the particular phone in question.<p>Apple already takes this risk with every since iOS release.