In an article about RFID chips in passports (cited below), the
following was written:
"The original article's concerns over the improvements in antenna
technology that might enable the ePassport to be read from a distance
greater than three to four inches are allayed by knowledge of the
laws of physics. Even supposing a criminal mastermind was able to
thwart the Basic Access Controls, the mutual authentication, the
robust encryption and the shielding technology in the ePassport
(which they won't), the power needed to read the ePassport's chip at
distance would have to be so great that it would incinerate not only
the chip within, but possibly even the ePassport itself."
I think that most criminal masterminds with a physics degree would
suppose that only a lack of advance in *passive* listening technology
would prevent RFIDs from being detected or read from a distance
(notwithstanding the other barriers, which are not at issue here).
But I may be wrong - are their *radio-based* active methods where a
signal has to be sent to such an RFID to get any signature? Perhaps I
don't understand the RFID technology in question here. The idea in
principle is that during the time when the RFID device is sending
information, it can only be detected from within a few inches, and
that no technology today can detect the signal beyond that.
Furthermore, even if an active device did have to be high power
because of distance, the power density at the RFID chip itself would
have to be no more than that of the nearby reader - again leaving the
mastermind with the main problem of how to passively detect the
return signal reliably at a great distance.
I'm not talking about the details of RFID protocol here, just the
invocation of "the laws of physics" to refute the basic argument.