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A Secure Off Switch for Cell Phones

Please don't use my cell as a covert listening device
  (+3, -7)
(+3, -7)
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Most people don't realize it, but even when cell phone are turned off- they're often not fully off. If some hacker (or 3-letter agency) decides to listen to you, they can remotely program your cell to transmit the sound to some designated number without you being aware, even when it seems to be turned off [see links]. For this reason, in high-security locations it's standard policy to require removing your cell-phone battery before you enter.

This always struck me as a rather crude solution. I'd like to see some brave cell manufacturer (or self-assembly kit) that installs a simple on/off switch to the battery of your cell phone (or to the mike if you still want to text). This secure switch will physically disconnect the wires when it's switched off, just like normal switches used to do. This seems like a trivial solution to get privacy, and have a longer lasting battery to boot.

Notes: * Even an amateur can verify that such a switch is really hooked up to the battery pack.. * Oh ya. And all this is equally applicable for your cell phone camera and laptop/PDA too.

imho, Jun 16 2009

Wikipedia: Covert listening device http://en.wikipedia...rt_listening_device
[imho, Jun 16 2009]

Schneier on Security http://www.schneier...otely_eavesd_1.html
[imho, Jun 16 2009]

[link]






       If you're that paranoid, just take the battery out. [-]   

       BTW, the cell-phone I'm looking at right now is switched off, and drawing around 200uA. If anyone knows how to power a GSM RF section off 200uA ('cos that's what you'd need to remotely switch this sucker on), I'd be happy to discuss an employment contract.
coprocephalous, Jun 16 2009
  

       ... if the switch was just at the microphone you'd even be able to still get messages (apart from the ones beamed directly into your head...)
loonquawl, Jun 16 2009
  

       //('cos that's what you'd need to remotely switch this sucker on)//   

       Unless a resident malicious piece of software woke the device up at specific, scheduled times, and then put it back to sleep (all the while without starting the display and keyboard locked?).   

       Can I have a job please?
Jinbish, Jun 16 2009
  

       //Unless a resident malicious piece of software //
Well, I could explain why that wouldn't work, but then I'd have to be jolly beastly to you.
coprocephalous, Jun 16 2009
  

       Firmware update then? Or at least, not so malicious software.   

       Dammit, shove a cron job on a Nokia N810... despite it having neither a cellular interface, nor analagous 'off' state (?).   

       (Any closer to that contract yet?)
Jinbish, Jun 16 2009
  

       I just wrap the whole phone in tinfoil. I always keep a large supply around, just in case.
miasere, Jun 16 2009
  

       //I just wrap the whole phone in tinfoil//   

       A tinfoil lined box would be reusable and the cat could provide an answerphone service.
bigsleep, Jun 16 2009
  

       If you regulary wrap youself in tinfoil, and keep the phone inside, then this is simply not a problem. [marked-for-irony] Solved with Tinfoil.
Aristotle, Jun 16 2009
  

       The whole point of this idea is that you can still use your phone when you need it. But conveniently disable it when you're at some critical strategy meeting, or making HR decisions, etc. To paraphrase the famous quote: "Just because you're paranoid, doesn't mean they're no listening in". And listening in to cell phones is incredibly easy for professionals.
imho, Jun 16 2009
  

       Um, a custom-sized sound-insulated plastic box to put the cellphone in, with a little white-noise speaker inside would keep any useful sound from being picked up. The phone could still get RF signals, and could activate an LED as a "ringer".   

       Cool, the Samsung 900 series of phones are most vulnerable. Mine is retired to playing audiobook MP3s under my pillow at night. Somebody is getting an earful of Jeeves and Wooster, slobbering snores and the occasional obscene grunting.   

       Which gets back to the anti-eavesdropping. Switch a music-player phone over to playing Bon Jovi's _It's_My_Life or just random noise--and damn anyone trying to listen in.
baconbrain, Jun 16 2009
  

       I thought top-secret types were required to pool all their cellphones in a shielded box at the start of such meetings. And that's not because the rest of the folks at the meeting are worried about somebody hacking your phone. It's because they don't trust individual members (ie, you) to ensure their phones aren't transmitting or recording. Besides, it would be very inconvenient to accidentally hit that button while in the middle of a conversation and have to reboot the phone. Mine takes a full 2 minutes 20 seconds to reboot.
21 Quest, Jun 16 2009
  

       I also would like an appallingly stone-aged "Off" setting.   

       For a DIY solution a foil-insulator-foil sandwich could be placed between one battery terminal and its corresponding terminal in the handset, and the outer foil layers connected by a switch.   

       On a stupid Sony-Ericson 'phone I keep as a backup I take out the battery, place a small piece of plastic film over its terminals, and replace it, so that it doesn't drain the battery or activate the alarm (which cannot be deactivated without a SIM card. Aaagh!). <rant> It is useless without a SIM card anyway, so there's no reason not to be able to turn it off. I hate phones that lock you out entirely when you don't have a SIM. I never consider buying handset+plan packages because they encourage such artificial stupidity </rant>.
spidermother, Jun 16 2009
  

       Spidermother, I have an old Sony Ericsson z500a and a z525, and neither have an *active* SIM inserted. I left the original SIMs in and they're deactivated, but I can access all the non-call and non-internet functions, including the organizer, alarm, calendar, games, phonebook, camera, and Bluetooth. Same with a couple of cheap Nokia bar phones and a Samsung flip phone. I use them sometimes for backup alarms and to play the games I downloaded to them. Why did you remove the SIM from your phone in the first place? Regardless, you can pick up a new SIM for about 25 bucks. So my advice to you is to buy a new SIM from whatever service provider that the phone came from, put it in, and enjoy.
21 Quest, Jun 16 2009
  

       I knew a guy who was sure the CIA collected every photograph ever taken from a cell phone.   

       After a few days, I managed to convince him that they were actually recording video, and that new phones had the cameras because older phones had them hidden in the speaker or earpiece, and somebody found one.   

       Paranoids are fun to screw with. I'll have to tell him about the tinfoil trick if I see him again.
ye_river_xiv, Jun 17 2009
  

       Just because the battery is disconnected, doesn't mean it can't eavesdrop. There may be a capacitor or spare battery on the circuit board somewhere, with enough capacity to keep the phone going for a few hours after someone switches it off.   

       Therefore, I think the best solution is indeed to wrap it in your spare tin foil hat. Yet another way this brilliant garment protects us from evil shadowy government surveillance types.
Bad Jim, Jun 17 2009
  

       [21 Quest] The Sony Ericsson is a free hand-me-down and came without a SIM. I use it as a backup when a charger for my main handset is not available. It's not really worth spending even 25 bucks on.   

       I stand by my dislike of the bundling of innately separate products such as phone handsets with plans, and computers with proprietory operating systems. I think such things disempower consumers.
spidermother, Jun 17 2009
  

       That's why I use an open-source phone ;D
21 Quest, Jun 17 2009
  

       *approves*
spidermother, Jun 17 2009
  

       "I just wrap the whole phone in tinfoil. I always keep a large supply around, just in case" I just use emergency blanket material (plastic stuff, we call it space blanket in the UK), it's less crinkly.   

       Also you could print adverts on the emergency blanket for anti-tracking device companies, or therapists.   

       One thing that really drains the battery when it's on on a lot of smartphones is the internet function, especially those with 3G or WiFi, or in my case both. I downloaded a neat battery-saving app for my phone, which keeps the battery from draining while it's turned on. It's called APN Droid (which is actually a misnomer, since it has nothing to do with my phone's Access Point Name/number provisioning with my carrier), and disables the internet capabilities while leaving the call functions intact. If I need to go online, I tap the app's icon, it re-enables the internet (only takes about 4 seconds), do what I need to do online, then tap the icon again and disable the internet. It makes a *huge* difference in battery life. Of course, it also renders some of my favorite widgets useless, such as the streaming news headlines, so I rarely use it...
21 Quest, Jun 20 2009
  
      
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