I was wondering if turning on Airplane Mode really disables all wireless connections.

If so, anything you do on the phone locally can not be traced, seen, or viewed, hacked, etc. by anyone over a network. Correct?

That is I can privately work locally without a network state, data submitted via programs through the web, etc.

  • You screen might still emit signals others could catch. – ott-- Oct 1 '13 at 21:21

Yes, “airplane mode” disables all methods through which the device voluntarily transmits information over wireless networks. That's the point.

The device is still emitting, of course. For example it emits visible light: all information that is displayed on the screen can be snooped by shoulder surfing or hidden cameras.

Even information that is not voluntarily emitted can sometimes be snooped. Whenever a variable current is sent over a wire, this creates an electromagnetic field; in principle, extremely precise measurements could reconstruct the data traveling on each wire. In practice, this kind of snooping is fairly easy for CRT displays (which emit a lot of radiation) and requires mildly expensive equipment for LCD. For anything smaller, it is all but impossible to discriminate between the many buses, or at least far more expensive than hiring a goon with a monkey wrench. This still leaves radiation as a side channel, but to exploit it, you really have to know what you're looking for.

For all practical purposes, a device in airplane mode used in a situation where no shoulder surfing is possible is immune to eavesdropping.

Note that if malware is present on the device, all bets are off. Malware could pretend that the device is in airplane mode when it isn't, or more simply, record data to send later.

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The "airplane" mode is supposed to deactivate all radio emission from the phone. Not the screen, though (the screen emits light, and light is a radio wave, albeit with a much higher frequency). Shoulder surfers can still be an issue (especially in cramped uncontrolled environments like in a bus or, of course, a plane). Also, some newer phones feature an infrared port which should not be deactivated in airplane mode, since infrared is not in the range of frequencies which is supposed to be shut down in airplanes.

Apart from possible "underhanded" emissions that a well-equipped attacker might detect (see @Gilles' answer; see also TEMPEST for a similar concept), there is also the possibility that the phone dutifully buffers what it would have liked to emit, and sends the whole batch of data as soon as he gets some network connectivity again.

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  • Buffering is the key vulnerability. Anything you do while offline can still change the state inside the machine, which can be transmitted or backed up later. And for the truly paranoid reader, note that the compass and accelerometers still work in airplane mode, meaning an inertial navigation system could still operate reasonably well without GPS or WiFi! :-) – John Deters Oct 1 '13 at 23:23

That's the idea, but a true test would be a radio receiver and a lab setting.

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