&gt; &gt; Asymmetric encryption<p>&gt; ...doesn&#x27;t protect against everything.<p>But it does protect against the exact threat model you proposed.<p>&gt; Defense in depth would be using cryto while requiring a physical connection.<p>&gt; Consider, for example, the people that made ATM shims that captured the card data while recording the PIN being entered on the keypad.<p>How about you consider it?<p>Building a facade to intercept physical communications is very much on par with building increasingly large, awkward, and expensive antennas in terms of difficulty barriers (especially if you need enough polish to blend in). I&#x27;m a ham, I would know. I&#x27;m not sure why you are so insistent on drawing the line between these two particular techniques.<p>&gt; A card that requires an electrical or inductive connection isn&#x27;t going to leak everything over the radio.<p>Are you familiar with the distinction between near-field and far-field? Because both RFID and smartcards span that distinction while you just tried to draw a line down the middle.<p>&gt; A smartcard is fine - my argument is against RFID.<p>Many (most?) smartcards communicate over RF. Your argument (and my rebuttal) was about<p>&gt; Adding radio as a primary component in a security system<p>not the RFID technology in particular. So do you or don&#x27;t you think RF communication in a security device is an inherent problem in and of itself?