Slashdot Mirror
Feds Can Locate Cell Phones Without Telcos
schwit1 sends along an Ars Technica report covering the release of documents obtained under the FOIA suggesting that the Justice Department may have been evading privacy laws in their use of "triggerfish" technology. Triggerfish are cell-tower spoofing devices that induce cell phones to give up their location and other identifying information, without recourse to any cell carrier. "Courts in recent years have been raising the evidentiary bar law enforcement agents must meet in order to obtain historical cell phone records that reveal information about a target's location. But documents obtained by civil liberties groups under a Freedom of Information Act request suggest that 'triggerfish' technology can be used to pinpoint cell phones without involving cell phone providers at all. The Justice Department's electronic surveillance manual explicitly suggests that triggerfish may be used to avoid restrictions in statutes like CALEA that bar the use of pen register or trap-and-trace devices..." The article does mention that the Patriot Act contains language that should require a court order to deploy triggerfish, whereas prior to 2001 "the statutory language governing pen register or trap-and-trace orders did not appear to cover location tracking technology."
No, most cell phones have one and only one battery.
And for low power EMF (cell phones) even very thin cages can be used, I wouldn't be surprised if most aluminum foil were more than sufficient.
For your Faraday cage to be effective, it has to be very conductive. The higher the resistance, the worse it works.
A thin layer of metallised Mylar is not going to attenuate the signal very much. Certainly not enough to prevent my receiving a call just now. I even tried sealing the end with aluminium tape (which, btw, is much better than duct tape for almost everything, especially ducts).
If you want to make sure some piece of electronics isn't transmitting/in a position to be heard, there are only a few tools that are up to the task. If you're in a hurry: hammer. If you want to be sure: nuke from orbit.
Can you be Even More Awesome?!
The thing is, you don't have control over the GSM/CDMA radio - it's controlled by a completely separate processor, and get access to the microphone, speakers, and a serial link to the main processor, so that the processor powering the phone's OS doesn't cause spurious radio transmissions.
Some data goes back and forth, yes, but you probably won't be able to tell when it's doing this versus a legit cell tower connection...
Do elaborate, please. RFID does, in fact, require power. It's just that that power is provided by the reader when in proximity to the tag. Are you suggesting there are RFID tags embedded into "modern cell phones"? Or something else? If you're suggesting that cell towers have the ability to blanket a region with an electric field capable of getting all of the cell phones to respond (loudly enough) to a "ping" for their location, I'm afraid I'm going to have to call BS. So what is this "functionality" that you claim allows cell phones to be identified and located without a battery?
Just as RFID tags do not require batteries to give disclose their location and unique identifiers, modern cell phones also have similar functionality batteries or not...
I am a cell phone designer, and a phone reporting *anything*, even just a handshake, to a tower thousands of meters away takes significant power.
It is possible that the little coin cell battery in most phones could handle the receiving of a signal, and then wake the phone up and have it reply with the main battery, (though to the best of my knowledge we don't let phones do that [and yes, I design power systems]), but if the main battery isn't there, that's a no-go.
Passive RFID is a completely different batch of apples than active cellular communications. Passive RFID has a maximum range of around 10 meters (phased array antennas notwithstanding, but seriously...). You would need a specially designed phone to use some sort of active RFID when the battery is removed, and we don't make those.
Now, this isn't to say that I'm not pissed at the Feds for doing something like this--perhaps even more so than the average user. I can see how they are taking advantage of perfectly innocuous and functional code and systems designed by my co-workers to agreed standards, and then using those standards to make our customers lose their privacy.
*sheesh*
>> Standing on head makes smile of frown, but rest of face also upside down.
Just so you know, here in Southern California, where the FasTrak system the parent mentions is, most toll roads that I'm aware of do not take cash. You must have the FasTrak, or presumably they will photograph your license plate and you will pay a hefty fine.
Here it's different than most places, of course; there are usually alternate routes you can take just as easily that don't have a toll. It'll just take you a little longer; the main difference being that the free route will have our notoriously heavy traffic or be jammed all the time, while the toll road you'll presumably fly through.
They dynamically adjust the toll depending on traffic level, to make sure the toll road is always operating at or below reasonable capacity. There are electronic signs at various points before the exits to these roads that tell you the current toll so you can decide to go that way or not. I've seen it go up to over $15 on the one near my house!
When I lived in New York (I just moved out here a few months ago) I had the EzPass for the NY Thruway, which was a little more nefarious. To get to any other city in New York in a reasonable manner, you have to use the Thruway, which is a toll road. I'm sure a whole lot more people in New York have EzPass than people in California have FasTrak. Of course, there are a lot more toll bridges and stuff in New York, which the EzPass also works on, which makes it, again, even more useful/essential than FasTrak since there aren't a whole lot of toll bridges around here (I can't think of a single one off the top of my head, while I regularly used them back in Buffalo.)