On Cellular Phone Privacy

Wednesday, Nov 23, 2005

I've been asked by several readers for their advice on cellular phones. First, I should mention that the cellular revolution still hasn't made its way to the Rawles Ranch. Perhaps it never will. I'd appreciate your e-mails with comments on this topic. (As a non-cellular kinda guy, I will surely leave out some important points.)

The general rules of thumb on cellular phones are as follows:

All cellular phones are vulnerable to interception--some are just a bit more secure than others. There is no privacy with a cell phone--or in essence with any other radio transmitter. None. Don't kid yourself. Take my word on it--back when I was an intelligence officer, what I did for a living was supervise troops that did primarily did voice intercept and direction finding. Please don't write to tell me that you saw on television that characters from The Sopranos use encrypted cell phones to talk with their mob buddies. Yes, it is possible, but there are three big problems with this: 1.) It is illegal for private Citizens to do so. 2.)  Doing so will instantly raise your profile in the eyes of authorities. Instead of being just one nondescript cell phone emitter in an ocean of emitters, your cell phone will suddenly become an "signal of interest." (SOI)   3.) Even an encrypted signal can still be DFed.

Regardless of the type of cell phone that you use, if you remove its battery pack then it cannot be tracked. It ceases to be an emitter. (Without a battery it will not even produce local oscillator noise.)

Privacy and anonymity are worthy goals, but consider that their may be situations where you will want to have your location known--such as when you are calling 911 in the event of a car accident, or in a wilderness rescue/medevac situation. IMHO, to the ideal solution would be a cell phone on which you can selectively disable the GPS circuitry.

When the U.S. FCC mandated "Enhanced 911"  ("E911"-- a.k.a. cell phone tracking), they set a standard for direction finding (DF) accuracy, but they left the method implementation up to the major cellular service providers. Some providers chose location schemes that depend on GPS chips. Others use time-of arrival radio direction finding. (The latter approach uses cell phone towers as the DF sites--creating a DF network with a very long baseline.) For details, see: http://www.edn.com/contents/images/198901.pdf  Because of this diversity of approaches, there are still many "loophole" cell phones that cannot be tracked or triangulated.  These include pre-GPS phones or phones with their GPS receiver disabled, subscribed in Sprint, Verizon, or Nextel service plan. But be advised that there is essentially no way to avoid tracking if your cellular provider employs time-of arrival radio direction finding. Do some research the next time that you change cellular providers.

The other important  aspect of cellular phone privacy is protecting your identity. Most cellular phone service plans require that you provide detailed billing information, a physical street address, and a credit card number. But what about those nifty "pre-paid" cell phones that you can buy at you local drug store?  For now at least, most pre-paid cell phones can be purchased anonymously.  They only lose their anonymity if and when you "recharge" their minutes with a credit card. (OBTW, I'll discuss anonymous credit cards in a future SurvivalBlog post. But here is a hint to get you started: the Simon's Mall chain sells anonymous pre-paid VISA debit cards.)

For more information, see: http://www.pcworld.com/howto/article/0,aid,114721,00.asp  and http://www.americanscientist.org/template/AssetDetail/assetid/47369 


Copyright 2005-2012 James Wesley, Rawles - SurvivalBlog.com All Rights Reserved