[LINK] Re: RFID in Govt, and in People
gramadan at umd.com.au
Thu Oct 5 23:31:39 AEST 2006
Interesting approach, but from may understanding, all you have done is
to make the RFID tag resonate, by bombarding it with radiation. And then
listening for the resulting resonate frequency.
As you correctly point out, everything has a natural resonate frequency.
The question is, is there is any useful information in the resulting
resonate frequency. (i.e is it being modulated)?
Charging in HF tags is done by induction. In particular the antenna coil
geometry is designed to transfer energy via induction.
I suspect that there would not be sufficient "inductive" coupling to
transfer enough energy to "charge" the RFID tag to power the microchip,
and thus modulate the resulting signal. Which is quite different from
getting it to resonate.
Yes I believe you have been able to detect the resonate frequency.
But I don't believe you have been able to extract a modulated signal
that you can read and decode to get useful data. You even hinted at this
- " I use the term 'reading' in a very loose manner."
Geoffrey Ramadan B.E.(Elec)
Chairman, Automatic Data Capture Association (www.adca.com.au)
Managing Director, Unique Micro Design (www.umd.com.au)
Adam Todd wrote:
> At 07:03 PM 4/10/2006, you wrote:
>> Adam Todd wrote:
>>> ... From 478 cm's away I could read the RFID with no problem at
>>> all. ...
>>> I'm not even going to begin with what happens after you can read it.
>> At 18:29 +1000 4/10/06, Geoff Ramadan wrote:
>>> 1) what device did you use to read the passport?
>>> 2) how was the passport presented. Was it opened or closed?
>>> 3) could you read it while it was closed.
>> In addition, Adam:
>> 4) do you mean that you:
>> a) extracted a bit-string; or
>> b) extracted human-readable data
> Prefer not to disclose.
> (Does that disclose something??)
>> 5) if b), could you provide some sample data.
>> (Naturally you'd want to avoid providing data with security
>> implications; so partial data or data that is, shall we say,
>> 'lightly falsified but indicative' might be best)
> I don't think it's possible to put sample data into a public place
> without the issue of security implications. I'll discuss it with my
> playmate and see what we can come up with.
> The "data" would in fact be, as explained on the passport, the same as
> the content of the passport in readable format. Again, I'd resist
> saying any more, other than to hint that privacy issues go beyond the
> To be honest it really wasn't that hard, but then when is anything
> "technological" hard?
> I should say that I've been working with One Wire touch memory systems
> and RFID devices for a LONG time now, since the late 1980's so this
> isn't a new concept to me.
> I use the term "reading" in a very loose manner. I won't say more.
> Look can I say something fundamental. I'm not adverse to RFID
> technology being used and I know damn well no matter how "encrypted"
> and "coverted" the data is, it can always be read, intercepted,
> duplicated and recreated. It's electronic. There are no means I know
> of to prevent replication of electronic stored data.
> DeCSS is great for DVD's in principal 99% of people don't care and
> haven't the ability, but 1% will always be able to find a way even
> with persistence.
> If there is a LEGAL WAY, there is ALWAYS an illegal way.
> Once the RFID is excited to transmit, that's it. It's in the open.
> There are ways to make low powered devices or even limited range
> devices gain range and become amplified.
> Lets face it, it's not that hard to build a listening device that is
> powered not by a battery but by the directing of day a 2Mhz RF signal
> in the direction of the device. The Higher the 2Mhz power the more
> excited the transmitter on the device.
> It's easy to detect low emissions of power (Star Trek has been doing
> it for decades!) it's even easier to detect emissions of RF.
> It's not difficult to detect disabled devices simply by resonating the
> circuits. I do it all the time. Depending on the location, type of
> equipment and the requirements, it's no different to finding room
> resonance by raising and lowering the frequency of your voice.
> (Didn't you do that as a kid to create a resonance?)
> My concern is more along the lines of the ease in which the device is
> excited, the ease in which it can be excited by high power excitement,
> and the fact that it potentially contains digital data that might be
> used for fraud.
> But then you just need a copy of the Human Visual page with a
> signature and photo, date of birth and you're away.
> How many times do you get TOLD and ASKED by people for your date of
> birth supposedly as a means of Security and Identification?
> Honestly a Date of Birth is meaningless as security. It's pretty much
> deemed public information to be honest.
> If you have a name and a DOB, you can pretty much find anything you
> want about a person. If you just have a Name, you are pretty helpless.
> Why can't there be a mismatch of data between the RFID and the Visible
> page - then you have a "checksum" or a "parity" checking mechanism
> that is HUMANLY untamperable.
> Enough said.
> If anyone wishes more information or discussion, please contact me in
> Link mailing list
> Link at mailman.anu.edu.au
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