Re: simtrac hw

MITM is useful to create a generic tool that is able to rewrite APDUs on-the-fly. Like a live apdu patcher. A sniffer only *listens* the sim<->reader lines, without writing anything. It's "passive" in the sense that all it does is listening. The timing is VERY important, a man in the middle will introduce latencies that can be *very* easily detected. It is essential that in a sniffer, all lines between the sim and the reader are directly, electrically connected, without any repeating hardware in the middle. In ALL situations, Vcc shall just be forwarded from the reader to the card. You can use an ADC line and a voltage divider to measure this line. This is important since a cold reset can be executed by the reader, and that will interrupt Vcc. And I see that the 3rd edition of ISO7816-3 now mandates that: "No card shall be damaged when the interface device applies a class not supported by the card". So the voltage is not important. My opinion is that in practice, all SIMs vendors, that will want their cards to work on the largest number of phones, will support all the 3 voltage classes (5,3.3,1.8V). If not, you cannot destroy a card by applying any of these 3 supply voltages. Sebastien On Mon, Nov 22, 2010 at 1:21 PM, Scott Weisman &lt;sweisman(a)pobox.com&gt; wrote: