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Comment by jimhefferon | Hacker News Reader

If a vendor provided a physical switch with which I could turn off the mic, that would be a feature that I at least would consider very attractive.

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That's in my proposal for a secure or private phone that I drop on people trying to build one. Hopefully it will get in a successful product at some point. Need one for mic, front camera, rear camera, and radios. Might compromise to have a physical switch for mic and radios with something inside phone (eg a jumper) to turn off others. I want to be sure I can cut actual power to mic and wireless, though.

If your threat model concerns with hardware/firmware exploits, then you can't trust the physical switches unless they cut all the wires - and unless you can validate that this is what they do. Theoretically speaking, a malicious (or threatened/persuaded/forced) manufacturer may implement a non-standard way to power the supposedly disconnected component using still-connected wiring, to be used for a special occasions.

/tinfoil

You should see my full write-up:

https://news.ycombinator.com/item?id=10906999

I went into detail on what it takes on hardware side:

https://news.ycombinator.com/item?id=10468624

Agreed, which is why I believe sound proof cases are the only sensible approach, and work with all current consumer devices.

This is why I got a shutter on m laptop camera. It's mechanicl, and I can see it's on or off. It should be a legal obligation to provide those, for camera and mic.

Regarding "legal obligation": in some countries the government may be the second main user of your camera and mic - next to you...

This is sadly true.

I want a DPDT switch that sits between the mic and the rest of the phone. That seems do-able to me.

I use masking tape over the camera, so I'm looking for a similar microphone solution.

(I don't want it inside the case, since I want to be able to flip the switch conveniently. Likewise, removing the battery is not what I want.)

Well, I just.. disconnected the mic in my laptop, the day it arrived (there is no webcam). As phones are concerned, I use my trusty SE ELM featurephone, so I'm not very worried about Googles, Facebooks, Samsunsungs...

I'd also buy such a phone. The switches to toggle each radio and sensor could be behind the removable back panel. I wish it were possible to easily disable in software mobile service without also disabling wifi and bluetooth as well.

At least on my Huawei P6 i can set it to flight mode and then turn back on wifi and bluetooth. Actually i have used the thing more like a PDA than a phone, as i have a well functioning HSPA capable featurephone that i pair up if ever i need data on the go.

> i have a well functioning HSPA capable featurephone

Make and model, please? I've been searching for something like that for a while now. Everything I've found is either carrier-specific, doesn't allow tethering, or is 2G only.

Long since discontinued, sadly. Its a SonyEricsson C702.

You mean it's a soft-switch that tells you it does that. You have no idea if the radio is actually running at any time or not. That plus their reliability issues are why I don't like soft-switches.

Well in my case there is no sim in the slot, so i can't say i care.

It still has an ID (IMEI).

That doesn't stop it communicating with the mobile network. At least in the UK, you can still call emergency numbers (999, Childline, Samaritans(?)) without a SIM.

>That doesn't stop it communicating with the mobile network. At least in the UK, you can still call emergency numbers (999, Childline, Samaritans(?)) without a SIM.

You haven't been able to do this since 2009. It was changed due to the high volume of hoax calls.

Huh. Someone should tell my phone; it still displays 'emergency calls only' when it is unable to connect to my own provider's towers.

>Huh. Someone should tell my phone; it still displays 'emergency calls only' when it is unable to connect to my own provider's towers.

That's emergency roaming. You can call emergency numbers provided there's signal from any network and you have a SIM installed.

If your are equip like me with a EMF meter, then its easy to confirm what your phone is doing when in airplane mode, with normally is nothing. A mobile phone is after all just a computer with a radio modem. It can't do shit without sending out RF.

I would recommend something like the 'Cornet ED78S RF Meter' to every technician with the tiniest amount of AU in circulation.

The reason I got it was because I have become electro-sensitive, and that's almost a death sentence in the modern city.

Those pictures of Stallman sitting on a mountain top and not a mobile phone mast in sight looked very appealing...

My phone LG-L80 99£ is GSM only, all else is off, apps downloaded on wired PC and installed via ADB interface.

Currently used as book reader for C++11 fourth edition and as Wikipadia offline reader(Kiwix) 12GB on SD card - music/mp4 player and the battery last for a week or more.

I feel I'm in control of my phone, don't know if that is justified or not?

What frequencies can an EMF meter pick up? One of my own designs of the past was to hide something in a cable to amplify a signal along 10GHz optionally with a beam hitting it. None of the WiFi security monitors looked for 10GHz. Neither did most cheap, spectrum kits.

The dedicated chips in phones with the radios could have extra functionality for other spectrum activated by a trigger, possibly received wireless signal. So, it's a concern to me.

The one I suggest goes to 6 Ghz

I can't imagine that pulsed digital transmission on 10Ghz would not create noise in the lower harmonics bands at all. The meter also have a sound mode where you eg. can hear the ~8-10Khz modulation of the mobile ~700/900/1900/2100Mhz signal.

You can clearly hear the difference between different transmission types as DECT phones, Wifi, GSM/LTE, and EM noise in general(PC's/HDMI cables/USB3 HD docks)

My central room heater has a small CR battry powered computer (that I had forgot all about) that calculate the bill and transmit the results every 2 minutes on 2.4Ghz

it makes a tiny ~0.5 sec pulse on the display/audio, and I thought for an hour that I had a hidden transmitter in my apartment, since turning the mains fuse off had no effect.

I had to clear the room of all tech to track down the source, felt a bit stupid when I finally found it.

So going down this road has some up's and down's vs staying totally oblivious of ones electromagnetic environment.

Appreciate the extra info. Might look into getting one. Lmao on the mystery of spying heater.

True, though with airplane mode they might be skirting the law as it now touches the whole interfering with FAA requirements are. Also it would seem it would be easy to verify for anyone who opens the case what the radio does.

That's not how subversion works. The subverted system will in fact turn off wireless in airplane mode. It's turned back on by a trigger. Stays on long enough to do the job. The commenters imply they would be using it outside an airplane. So, FAA wouldn't even notice.

Sell a micless phone. Actually, it's a tablet, and if you want it to go into surveillance / phone mode, you plug in your own goddamend mic. Most headsets have one.

Alternatively: a phone whose "off" mode is a battery eject.

Re battery eject: How can you be sure that the removable battery is the only one?

Fair point. Proofs are hard, but on a mass-market device, considerable secondary storage would be fairly evident in a teardown.

Microcurrent devices fed by a small cap or disguised secondary battery might function. But you'd have very limited capabilities.

You might well ask how sure you are that there's not a secondary microphone on the device, to which I can only suggest you cannot be too paranoid.

Brilliant. Never even occurred to me. People often use headsets, wired or wireless, for the mic. Can just not enable audio unless one is plugged in. That's so easy to verify. Thanks for stating the obvious to my overly-complex mind. :)

I've always found built-in/integrated cameras/mics to represent tremendous negative value.

1. I cannot unambiguously disable them.

2. I cannot upgrade / swap them readily for something better.

Aftermarket/detachable just seems such an obvious alternative.

And yeah, a simpler solution to a hard problem ;-)

See slide 30 on this Neo900 presentation: http://neo900.org/stuff/ohsw2014/ohsw2014.pdf

Also see the various kill switches on the block diagram (GPS kill, modem monitor, mic not directly attached to modem (so you could probably send fake audio/silence),etc: http://neo900.org/stuff/block-diagrams/neo900/neo900.html

See slides 16 through 23 here for some details on the modem/audio monitoring/separation: http://neo900.org/stuff/cccamp15/ccc2015talk/talk.pdf

Would this meet some of your criteria? If there is something missing you can discuss with the people involved (on IRC usually): http://neo900.org/contact

It meets some of my criteria. They're doing good work. Gotta ditch that TI processor when possible. Need some hardware and software modifications. However, actual switches for power and audio coming through Linux part are positives. Removes some low-hanging fruit.

> my proposal for a secure or private phone that I drop on people trying to build one

Can we see it?

Here's my write-up on securing Tor that shows issues and mitigations from high-assurance security in action with my own style:

https://www.schneier.com/blog/archives/2014/09/identifying_d...

Here's one write-up of similar methods applied to mobile:

https://www.schneier.com/blog/archives/2014/06/blackphone.ht...

Here's some links to HW and SW techniques that might be used in SOC to knock out the 0-days:

https://news.ycombinator.com/item?id=11848132

Note: You can see difference between few in real security on HW side. Mainstream, faux security immediately says IOMMU, stateless, whatever. High-assurance, real security is concerned with segmentation, pointer protection, making memory untrusted, TCB effects, optionally timing of ISA operations, and so on. Apps + their CPUs get hit all over. Securing one takes more than a mere IOMMU or something. ;)

Yes, but maybe this is too ambitious. Maybe, for now, we should be happy if we can remove the battery.

Common workarounds include disconnectable devices like USB microphones, or creating your own hardware shields like electrical tape over a laptop webcam.

This is more a plug for the EFF than it is for a product, but these camera stickers have served me well and helped strike up a healthy conversation about privacy - https://supporters.eff.org/shop/laptop-camera-cover-set

After Snowden I just took a pliers to my laptop and ripped out the mic and webcam. It felt great.

Speakers can be used as microphones....

Very very shitty microphones, so the statistical risk is significantly reduced! And the hardware might not support doing that switch in software.

Actually, you can get pretty good quality (You could easily do speech-to-text on the produced audio)... If you want to do a simple test, plug-in your headphones into your microphone jack and start recording away. I just did it why my current cheap Amazon basics headphones and I can clearly hear my speech back. Also take a look at https://www.youtube.com/watch?v=GqNrLfbwAH8, I think that this shows you how to record from your laptop's speakers in Windows using Audacity.

True.

The video: No, it shows how to 'record what you hear' (windows mixer) nothing to do with the speakers.

I would claim that it is impossible to record from speakers that are connected to low impedance running output amps and record from them at the same time.

So if the speakers are playing music they are not recording your sing-a-long also.

Your solution is more foolproof, but Micro Snitch[1] is worth looking at - same company behind Little Snitch.

[1] https://www.obdev.at/products/microsnitch/index.html

might be a future option for Google's project Ara.

I'm not seeing that. Certainly I'd expect their basic phone to come with a mic. I want a way to physically disconnect an existing mic, not to connect a new one. Am I off here (probably ..)?

The Ara is a modular smartphone system. Since there's a clear benefit to being able to remove the audio/video/wireless modules, I would hope that they are fully replaceable and separate from the screen and CPU modules.

I figured they could even make a phone without any microphone and then let users plug in a headset when they want to make calls.

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