cell phone anonymity

[Phillip Zakas]

Just a minor correction to the below posting: cell phone locations are NOT
calculated using GPS.  They're triangulated via the three nearest cell sites
reading the cell phone signal.  Accuracy is much lower than with GPS, but
good enough for cops to, say, find a stranded motorist on a highway.  I
believe resolution is somewhere around 40 meters in densely populated areas
(where there are many cell phone towers).  This resolution figure varies
from region to region.

GPS, as you know, relies on the satellite GPS system which requires special
electronics and antenna systems that neither US-based (cdma, tdma, etc.) nor
Europe-based (GSM) nor Japan based cell phone systems incorporate into cell
phones.  The only system which MAY have included GPS (but I don't think they
included it though they could have) was IRIDIUM, which is now used by the US
Navy and US Special Forces units for remote communications...yes IRIDIUM is
still alive and kicking.  Turns out their satellite-to-satellite
communication, which uses direct laser communication, is pretty secure. :)

IMHO, the real privacy issue with cell phones is the security of a
conversation.  Digital cell phones use padded encryption keys which
effectively dummy down overall encryption.  If you cryptanalyze a
transmission you'll find a nice, consistent pad of zeros in every key (how
thoughtful to make the padding so consistent!)

phillip zakas

-----Original Message-----
X-Loop: openpgp.net
From: owner-cypherpunks at Algebra.COM
[mailto:owner-cypherpunks at Algebra.COM]On Behalf Of Ray Dillinger
Sent: Monday, January 08, 2001 12:59 AM
To: Multiple recipients of list
Subject: Re: cell phone anonymity






On the larger purchases, the costs drop down to the forty-cents-a-minute
range.  Totally worth it if you really *need* anonymity on the phone.

Of course, anonymity is relative; these phones have built-in GPS chips
for 911 calls, and these are activated from the central office, not by
a 911-sensing circuit in the handset.  IOW, it is not impossible for
someone with the right gear and knowhow to query the phone for its
exact latitude and longitude at any moment when it's in use.  (I don't
know whether it can be queried when it's switched off, nor if so whether
removing the main batteries will stop it).  So if you're into hard
anonymity, keep it inside a faraday cage when you're not using it and
don't use it from inside your own dwelling.

Faraday cages don't have to be fancy; a fruitcake tin will usually do.

					Bear


On Sun, 7 Jan 2001, Paul H. Merrill wrote:

>But, the rates on the prepaid services are
>exorbitant, almost a dollar a minute for the
>smaller recharges and they never do get good.  As
>always, you don't get more than you pay for.
>
>PHM
>
>Andrew Jenks wrote:
>>
>> In the US they are now selling prepaid phones in electronics stores,
>> computer stores, and -- my favorite -- some Blockbuster movie rental
>> locations.  You go in, pick up a box, pay cash at the register, and
you're
>> done.  No information is required at the time of purchase.  Refills
>> available from various retailers depending upon your service company.
>> Again, you walk in, pick one up, pay cash, and leave.
>>
>> -----Original Message-----
>> X-Loop: openpgp.net
>> From: montag montag [mailto:cels451 at yahoo.com]
>> Sent: Sunday, January 07, 2001 10:07 AM
>> To: cypherpunks at toad.com
>> Subject: cell phone anonymity
>>
>> Please post the actual experiences about obtaining a
>> pre-paid cell phone (aka "mobile" in the less
>> developed
>> world) without revealing any (correct) identifying
>> info,
>> such as address, telephone no, name, etc.
>>
>> I know that it can be done in Canada. Unsure about US,
>> UK and the rest of europe.
>>
>> regards,
>>
>> __________________________________________________
>> Do You Yahoo!?
>> Yahoo! Photos - Share your holiday photos online!
>> http://photos.yahoo.com/
>
>--
>Paul H. Merrill, MCNE, MCSE+I, CISSP
>PaulMerrill at ACM.Org
>
>