Google really needs to release a dedicated "Crime Mode" so we don't need to keep using this airplane mode workaround.

$9.99 a month "identity masking", lets you run your android device in stealth mode. (I'm being sarcastic of course).

One of my SDR projects was to boot a GSM base station if my burglar alarm went off and store copies of every IMEI it can see in the cloud. Seems like it would be a better lead to hand investigators than a fuzzy security camera shot.

It's a great idea but is it legal to operate a personal Stingray?

Yes! Well let me be a bit more clear. The FCC has a process for, and indicated they would likely approve, a special temporary operating license for such a device given that it would only operate for a short time (during the break-in) and not interfere with the thieve's or neighbor's cell phones as it would respond with no compatible roaming network. Also it wouldn't do any sort of interception or monitoring other than the tower ping.

It would also need permission from the licensed spectrum holder, that could be harder to get.

But yes, completely legit with the right paperwork.

Wow, I'm a bit surprised by that. Thank you for answering.

I was a little as well, I happened to be at an SDR conference and one of the attendees was a lawyer working with the FCC on licensing issues[1]. I gave him my use case and he said that if it was constrained the way I said it would be, then if it came through their office they would likely approve it.

[1] The FCC has been pretty engaged in understanding the impacts of SDRs because of their potential for abuse (as one attendee called it, "The Drones of spectrum." As an amateur (AI6ZR) and someone in industry I've been helping as an SME to explain some of this stuff to their less technical staff.

And investigators probably would not care — consider how many identity theft cases have the ID thief on camera (in my case, at a hardware store opening up a line of credit in sight of store cameras, and later using a cloned card at an ATM machine, surely in view of an ATM camera.)...yet despite thousands stolen in ID theft cases, there is hardly ever any action taken.

My thought would be they could track the phone of the person, who would probably still have it on them, and using that and a fuzzy security camera image have enough evidence to arrest them at least.

The whole "jailbreaking the phone" business gets suddenly a completely new meaning...

I feel like, as soon as you enabled this feature, your phone would start broadcasting more.

I suppose we can sorta thank the FEC for their crazy broadcast device requirements when it comes to suspecting whether airplane mode actually stops a device from dialing home.

I can see the mental gymnastics now:

"Criminals deserve just as much privacy and safety as anyone else. If the government violates the criminal's rights to solve, prevent, or preempt crimes, even more crimes have occurred (privacy violations, killing of the criminal, etc.)

There should be explicit modes for phones and browsers available to criminals that allow them to safely commit crimes without risk of their rights being infringed upon."

I know you were being facetious, but a mode somewhere in between "track me" (data enabled) and "remove my phone from the network" (airplane mode) would be nice.

Maybe "for the next hour, don't do the normal location-tracking/biometrics monitoring/reporting". I get that Google has no incentive to make that feature but maybe Apple does?

Basically every normal adult commits at least misdemeanors daily (in the sense that a bored cop could stick you with one and an aggressive prosecutor could nail you for it if you didn't get a decent lawyer) crimes all the time.

Trying to make a black and white distinction between criminals and everyone else is futile.

>Basically every normal adult commits at least misdemeanors daily

This. Drive 5mph over the limit? That's a crime. Buy some stuff off craigslist? I hope you paid sales tax on that, buddy.

Well, who defines what a crime is? The problem starts there, I'd say.

That sounds plausible in the UK

They can't call it that. But they can call it... Incognito. Plus then you can just tell the cops: "i was watching xhamster all night.. see my phone was in porn mode (you know incognito is called porn mode)"

> That's why you do crime in airplane mode

Heh, are you a fed? ;)

>Google is tracking you. Even when you're in Airplane Mode without SIM card

https://www.youtube.com/watch?v=S0G6mUyIgyg

Your locations from the time your phone was in airplane mode are uploaded the moment you switch it back to normal Wi-Fi connection. I guess your only choice is going full-on tinfoil/Faraday cage-style though that might be a bit impractical while doing the deeds...

The entire premise of this is flawed; instead of trying to come up with a way to make the tracking device you're carrying stop tracking, maybe you should just not carry the tracking device in the first place. Leaving your phone at home when go and rob a bank is like Criminal 101.

And how exactly are you supposed to Uber to the bank and back without a phone??

I'm surprised I had to come this far to find the reasonable answer. Opsec 101.

It's not the only reasonable answer. Leaving your phone powered on and at home works too. Powering it off might stick out, actually.

The comment I replied to said nothing about turning your phone off, only leaving it at home.

> you should just not carry the tracking device in the first place

Baseband processor might be running even on a phone that is seemingly turned off. That's why crime bosses discussing breaking bad always removed their batteries. That might also not work 100% if there were large capacitors inside the phone...

You might need Maps to avoid traffic on your way out.

it's conceivable with even the phone powered off that the GPS processor could still be running in an ultra-low power mode doing geolocation fixes every n-seconds and storing them in a cache on the chip.

So I guess a Faraday cage would be the only sure way...

I've done some neuro/ephys related collaborations where I installed stuff inside a room sheathed in all 6 sides in solid, grounded copper. Inside with the door shut, the wifi and LTE were both good enough to stream video!!! Although, they say it did a good job at cutting the 60hz noise. Personally I would learn a little bit more about Faraday cage design before trusting anything to it besides lightning strikes

Interesting! Do you think the signal propagated through the copper or snuck in through some hole or slit?

High-frequency emissions love long thin gaps. Just grounding the parts against each other is not enough, you have to close the longer gaps, eg with copper tape with conductive glue (sold in electronics shops) and the surface below must be blank too. If you do not do this the gaps might even function as an antenna and amplify the signal.

Also, cables coming outside of your box must be shielded too.

Typically there was a 2" conduit carrying DC power cables and the seam around the door might not have been sealed, so probably that. Also had similar results with fridges, and they have rubber seals on the door gap. So probably leaking through cracks.

If we go into questions of what a maximally malicious phone could do, rather than a question of what a normal phone actually does...

The Faraday cage would still leave the accelerometer fully functional. Now you might say "but because of drift it will rapidly diverge". Yes and no. It turns out that it's possible to detect based on "gestures" where you might be. Works better for winding irregular streets than in a gridlike street network.

If we go full Sherlock Holmes, the microphone might also overhear trains and music from stores giving away the location.

Or turn it off. Or leave it at home.

Is that true on Android? On iOS location APIs just don't work in airplane mode.

I just tested this on my iPhone and location works just fine in airplane mode, even with WiFi off.

It's probably using GPS, which AFAIK is not affected by Airplane Mode (probably because it's passive?)

I wonder why. Mine doesn't work, it says location could not be determined. iPhone 7, iOS 12.4.

Android allows the user to turn location on in airplane mode.

Yes, I do this all the time when I'm hiking out backpacking. Without any cell or WiFi nearby I try to save battery by turning them off. When I want to check a location on my map I enable the location long enough to get a GPS fix and turn it off.

I certainly do not trust my phone to turn all radios off on airplane mode or with wifi or bluetooth shut off.

I could pretty easily verify my suspicions but I think others already have.

Reminds me of https://gizmodo.com/automatic-wifi-login-helped-police-id-te...

Airplane mode doesn't turn off GPS. What you want to do is turn off location, or location history at the very least.

I have to wonder why Google removed the ability for apps to put a phone into airplane mode / turn off the GSM antenna. Perhaps it was a legitimate UX consideration or some weird unintended consequence of a regulation about radio transmissions.

Still, it would be nice if the default for phones was to not be connected to the mobile network. Instead, they could listen out for a signal broadcast on an FM frequency (for example), and only connect to the mobile network when a specific unique ID was sent, indicating that you have an incoming call. (The unique ID would be agreed with the radio transmitter in secret before hand, and changed after each call).

When your phone is on a Wi-Fi network, it could instead have all incoming calls directed to it that way, like a softphone, meaning you would only rarely have to reveal your location to the mobile network.

The economics of this could work in some places (based on my rough guesses), but not if users had to root their phone to grant apps this permission to turn airplane mode on and off. I also don't know how much battery life would be required to be constantly processing an incoming FM signal in software (at least whenever the phone was off a Wi-Fi network). I'm also assuming that phones have FM receivers that apps can interact with, or that this could be an external device, connected via BlueTooth, perhaps.

I wish I knew what is apparently so objectionable about my comment above. Is it just that the system I'm proposing is impractical for some reason, or do people object to the goal of preventing governments from tracking the movements of basically all their citizens all the time?

As an example of the sort of society I am hoping to avoid, let me offer this article:

https://www.theregister.co.uk/2018/05/11/top_judge_mulls_com...

Probably an annoyed location data salesman?

In all seriousness though, I'm pretty sure your system fails in the deliverability department.

Mobile phones are meant to be...well... mobile, and that functionality basically requires that when a call intended for you is started from somewhere else, there has to be a way for the signal to get correctly switched to where you are.

If you treat cell towers as switches, that then means that each tower maintains a routing table of handsets within it's area which allows the signal to eventually find it's way to you. This is the fundamental operating principle behind packet switching and the Internet in general.

Let's say there's 4 cells. A, B, C, and D.

I call you from A. You're in D's coverage area. A can connect to B and C, and C can connect to A, B, and D, B cannot see D.

My handset tells the switch behind cell tower A I'm looking for you. It checks it's routing table to see if it's serving you, and finds it can't, so it pings the next switch that has announced a possible route (C). C checks it's routing table, to find you and doesn't, but it sees D knows of you, so forwards to D. D knows you're there, so it finally connects the call. The circuit is made. This works because information about what handsets are in range, and which cell knows routes to what is constantly updated and propagated through the network. So if you took a trip out of D to B while on a call, the call would not have to terminate since the towers hand you off from tower to tower as your handset's location changes.

The system you propose though, breaks that paradigm. Since the cell tower has no way of tracking the handsets in its service area, every possible tower has to chirp to see if your phone will respond. Once your session is established, some of the normal routing protocols can still be reused, however, the initial connection stage is where it gets problematic.

Routing tables clean themselves up over time, so if you don't use your phone for long enough, you essentially cause the system to attempt a network-wide chirp just for you.

Now multiply that by everyone, times the timeout to voicemail, on every tower on the network. Not ideal. You have no way of telling whether the call connected with the handset until the handset actually answers, or every switch gives up and returns cannot connect as dialed. You're a walking DoS attack because someone wants to call you, and you won't pick up your damn phone.

Furthermore, your scheme degenerates to the current arrangement if an always available mobile data connection is assumed, as your phone will just establish a session every time it sends data.

Basically, it's not the telephone part that makes you traceable. It's the "I can guarantee synchronous delivery part". And hell, even if you throw out the mobile bit, phone records still the you to a location; it just takes a bit more footwork and a cooperative witness/wiretap to prove it's you.

It's a pretty in depth problem, with a lot of nuances to be squirreled out. It takes a long time to explain, and even if someone could get most of the way there, that's only the start of the issue. I've got friends who have tried making ISP's before, and the amount of friction created by monolithic telco's is absolutely insane even when you aren't doing anything exotic.

You have to remember as well, telephony isn't magic. You're eating up bandwidth all the time. Stuff is incredibly fast nowadays, but everyone is using it too. Also, all successful networking suffers from tracibility problems. Things just get mitigated slightly by jurisdictional boundaries and the impracticalities of being able to trace through sufficient levels of proxy links. So it's not surprising you got a few "you really don't get it" downvotes.

Anyway... Hope that explains things, and I'm sure there's a bunch of detail I'm missing.

EDIT: Additional thinking: there's other reasons why a telco/mobile provider would want all handsets connected at all times even when not doing calls. It gives them an idea of where they need to install or upgrade infrastructure based on metrics w.r.t how many handsets are in the cell.

Basically, from a business standpoint, there is little reason to not go the direction that we have. The privacy concern does change things a bit. Not sure whether it would be enough to drive a push to abandon/change things so drastically. It's an interesting thought experiment though that I will happily cogitate on for weeks in my idle time. I like devising new protocols.