Discussion on:

Hackers can follow you via your cell phone

There are a few ways that come to mind on how to protect the information.
1) Encryption of the information, possibly something as simple as having a surrogate
phone # to act as an alias with this surrogate changing on a fairly frequent basis.

2) Have false information broadcast in addition to the real information which masks
the signal. The problem with this is the fact that phones have to work with
multiple systems which need access to the information and likely the system will
be cracked.

3) Have a more passive system so that if there is no phone call there is no tracking.
This is suboptimal since it would require an incoming call to alert many areas
to attempt to locate the phone, possibly overloading the capacity of the current
system as an entire region must be checked

The surrogate number will be more or less permanent because this will be the 1 that gets distributed. The real number will be the 1 that gets periodically changed. This would be implemented by swapping SIM cards. I assume service providers can reprogram SIM cards so that there won't be a new source of e-waste.

I think this technology would only permit a hacker to know if/if not you were in a particular cell grid, after he called your cell number (if he new it).

From the Univ. of Minn. Article: "Another example could be thieves testing if a users cell phone is absent from a specific area and therefore deduce the risk level associated with a physical break-in of the victims residence."

From Yale.edu article on How Cell Phones Work: http://www.yale.edu/ynhti/curriculum/units/2003/4/03.04.07.x.html
"The major component of the cell phone system is the cell. The cell phone system divides an area of service into a set of cells on what might look like a hexagonal grid. A phone tower or base station in the center of the cell covers an area of 2 or 3 square miles around the tower. Cell phones transmit to towers, which then connects you to the normal land based telephone system to route the call. In other words, a handoff has to happen when you move from one cell to another. A typical large city has hundreds of towers and each carrier in each city runs what is called a central office, known as the mobile telephone switching office (MTSO). For example, as you drive from one city to another every couple of miles, the system hands off to another cell. You don't realize that is happening because it is not noticeable. Let us look at what happens when someone calls you.
First, when you power up the phone, it listens for special frequencies (control channel) that the phone and tower use to talk to one another. If there are no control channels, the phone displays a message no service, because it knows it is out of range. Second, the phone transmits a registration request, so that the MTSO keeps track of your phone location in the data base. It is important for the MTSO to know which cell you are in when it wants to ring your phone. Third, the MTSO gets the call, and it tries to find you by looking into the database to see which cell you are in. Fourth, the MTSO chooses a frequency pair that your phone will use in that cell to take the call. Fifth, the MTSO communicates with your phone over the control channel to tell it what frequencies to use and when your phone and the tower switch on those frequencies, you are connected and talking. And sixth, as you move toward the edge of the cell, the cell tower notes a diminishing signal. The diminishing signal indicates that it is time for the control channel to hands off you to the next cell."

Place your account under a fictitious name. Then the only people who will know it's you they are tracking are those who know your number. This can be a disadvantage if you have friends who become enemies. You can also use skype or another VOIP service under a different number. Data calls are harder to track than cell calls.

Depending on what has been downloaded to your phone. You can be followed from room to room. Mr RJ Hartman comment is way off. If you want to know for sure that you are not being followed or even listened to. You must block all wifi going to your phone and coming out of your phone. Yes it does not matter if your phone is off because it is really is still on. That is just the facts. Our products at MIAmobi can help if your feel it is a problem.

It looks and is scary. Thanks to Christie for bringing this up.Surrogate number is really a good solution, will it be feasible?

Tracking someone is easy - FINDING them is hard.

The announcment does not mention that the eggheads made a lot of assumptions and created a bunch of special situations to find the phone they wanted to track. The most important quote from the paper that was left out of the announcement is: "if the victim lingers within 1km of the tower for a couple of minutes, our attack would succeed." So if someone is moving fast relative to the cell or is in a smaller cell, the attack is useless. You can read the paper here: http://www-users.cs.umn.edu/~foo/research/docs/fookune_ndss_gsm.pdf

The researchers rely on statistical methods to find the phone by forcing it to respond to the tower and capturing all the responses in the cell within a specific time period based on the GSM protocol. They generate a set of responses and use them to sift out the recurring ID codes. They also need to know where all the towers are so they could map the responses. This is not hacker stuff in that you just can't just pick up the equipment and start following anyone.

People these days intentionally install apps (like Foursquare) that literally broadcast their locations and goings-on in realtime. This won't seem so spooky to people once us old-timers are out of the loop. It's a brave new world...