Apple's T2 chip will prevent hackers from eavesdropping on your microphone

Post by djrogers » Mon, Nov 05, 2018, 12:07 AM UTC

ridgeguy wrote: post #75

pulse7 wrote: post #53

Earlier quoted context omitted.

Physical switch could be made INSIDE the laptop and would be automatically pressed by the lid itself - when the lid is closed. No sensors needed. No chip needed. When lid is closed - mic is disconnected. When opened - mic is connected... User does not need to do anything else then closing the lid...

Physical switch could be done with a very small magnet behind the lid surface and an opposed micro-reed switch (or other magnetically actuated on/off device) buried behind the body surface. No surface penetrations, no exposed moving parts (reed relays are hermetically sealed).

Post by newnewpdro » Mon, Nov 05, 2018, 12:13 AM UTC

XMPPwocky wrote: post #55

newnewpdro wrote: post #45

Earlier quoted context omitted.

Which will all be inside an IC, away from the microphone. So what, does the light turn on whenever the entire IC sees power? Because if it relies on a signal from within the software-controlled IC, that's not exactly trivial to audit.

The trivial solution would be a LED + resistor just wired across the mic's power rails.

Post by andromeduck » Mon, Nov 05, 2018, 12:22 AM UTC

shawnz wrote: post #56

GuB-42 wrote: post #24

Earlier quoted context omitted.

There is already a lid closed sensor. Adding another mechanical switch is more expensive, adds another point of failure, takes space, may interfere with the aesthetics, etc... The T2 chip probably also acts as a controller for a lot of the builtin sensors, including the microphone and lid closed switch. As a result, adding a feature to turn off the microphone when the lid is closed becomes trivial. Basically just add…

Why have the control go through a sophisticated programmable chip and not just use a simple transistor/relay directly connected to the sensor?

Post by jloughry » Mon, Nov 05, 2018, 12:24 AM UTC

wongarsu wrote: post #73

askvictor wrote: post #64

I recently learned that LEDs can be used as light sensors if connected to an ADC. I wonder what other mechanisms there might be to capture sound that a determined adversary (i.e. government organisation) might use. While speakers can certainly be used as microphones, I doubt they'd be connected to an ADC so probably won't be useful, but what about the multitude of other sensors?

> While speakers can certainly be used as microphones, I doubt they'd be connected to an ADC so probably won't be useful In most modern PCs with two audio jacks software will ask you what kind of device you just connected and reconfigure the sound chip to treat it as input or output. I wouldn't be surprised if clever software was able to convince Apple hardware to treat the built in speaker as a microphone.

Post by lstodd » Mon, Nov 05, 2018, 12:31 AM UTC

dpkonofa wrote: post #61

lstodd wrote: post #46

Earlier quoted context omitted.

Those are rated for over hundreds of millions of switching cycles. They would be the last thing that breaks in a laptop. But if you're so against moving parts, a hall sensor and a transistor would achieve the same result.

Or, you know, they could use a chip that they're already putting into the device (like the T2) and not have to use additional components. Same end result without the extra parts.