If computer privacy is critical enough that many laptops now include a physical webcam shutter, why can't you do the same for the microphone?

It’s a question that PC makers should be asking themselves. Some, like Dell, say they’re working on a solution. But for whatever reason, reassuring customers that their conversations aren’t being monitored doesn’t seem to be a high priority, especially with consumer laptops. Fortunately, one recent model from HP signals a way forward.

Amazon and Google We now live in an era where we demand always-on connected services, and yet we’re terrified that someone else is listening.

A future where everything listens to you

Part of the problem simply may be the inertia driving us toward an era of always-on, always-listening devices. At their respective developer conferences in May, both Microsoft and Google suggested a future where a user would trigger an assistant with a wake word, and then an interactive conversation would take place naturally. Currently, assistants like Cortana and Google Assistant end the conversation after a single query. In Microsoft’s Cortana demo, the conversation lasted for several minutes. But there was no “thanks” or “that’s all, Cortana” to signal the end of the exchange and tell Cortana to stop listening.

Consumer expectations may be another driver. At least a subset of users seems to think that a device that isn’t always listening to them is in some way defective. Consider the customer responses before the other major assistant, Amazon Alexa, responded to wake words within Windows 10. (Yes, there are now two digital assistants capable of listening to your every command, built right into your PC.) Alexa’s inability to listen in was viewed as a critical shortcoming.

Michael Brown The 2nd-generation Amazon Echo has an array of seven far-field microphones mounted on top, but also a button (at left) to turn them off.

Here’s the thing: Even if they buy always-connected smart speakers, consumers do care about privacy. That’s evidenced by the fact that most smart speakers like the Echo Dot now include some form of physical button for disabling the microphone.

We don’t know much that button is actually used, but there’s an important reason to have it. We know that Amazon, Google, and Microsoft aggressively collect as much data as you’ll allow. As Geoff Fowler of The Washington Post has chronicled, Amazon’s Alexa squirrels away dozens or hundreds of interactions she’s sampled. If you were an early adopter of a device like the Echo Dot, those recordings go back years.

Another fundamental problem is that when Alexa isn’t sure whether you’ve summoned her, she errs on the side of Amazon, not you, Fowler found. Even if it turns out that you haven’t asked anything of Alexa, the recording still exists. Your PC simply gives assistants like Alexa another way to collect information.

PCs already protect you from spying webcams...

While few laptops control their microphones as easily as smart speakers do, controlling webcams is an established practice. Consider the official and unofficial “privacy shutters” that adorn notebook PCs today—everything from adhesive tape and Post-It Notes to more sophisticated solutions, like the ThinkShutter on some of Lenovo’s ThinkPad notebooks for businesses.

Mark Hachman / IDG Lenovo’s ThinkShutter is a physical shutter that you can slide over to block the Webcam.

But don’t discount the even greater impact of someone overhearing what you have to say: your finances, college plans, sales pitches, an R&D breakthrough, your company’s five-year-strategy, legal troubles. In the right context, especially a business environment, information captured from a hot mic could be incredibly damaging.

The difference is that it’s relatively trivial to prevent your PC’s camera from seeing you, but there’s no comparable physical “kill switch” available to turn off your mic. Hackers may no longer be able to see you, but they sure as heck can listen in.

...But they’re not doing enough about hot mics

Unfortunately, not all notebook makers appear to be giving the mic issue as much care as the camera shutter. While some notebooks now include dedicated keys to mute the mic, including the Lenovo ThinkPad X1 Carbon , far more are making it potentially easier to spy on you. Microsoft’s Surface lineup lacks hardware controls for disabling either the camera or the microphone; though you can disable them in the Windows 10 Settings menu, we're back to the question of whether both are really off. And it’s not just one mic, but many—most laptops ship with “far field” capabilities specifically designed to pick up and recognize your voice at a distance, even across a crowded room.

Mark Hachman / IDG The Lenovo ThinkPad X1 Carbon includes a function key to disable the mic alongside the ThinkShutter, but it’s more of an exception than the rule.

Even if you disable the camera as well as the mic within Windows Settings, it may not ever be completely off. On a Microsoft Surface Laptop, for example, Microsoft explicitly allows Windows Hello to access the camera, even if you disable it. Win32 apps (.EXE files) aren’t subject to Microsoft’s controls—they can access your mic and camera as they wish, and there’s nothing you can do about it. Microsoft itself throws up its hands while describing the problem: “For more comprehensive protection of your personal data associated with these settings, you could consider disabling these devices.”

We may have a solution

The question, of course, is how to disable them. Save for swaddling your laptop in blankets when not in use, there’s no obvious way to reassure you that your mic is physically unable to hear you.

HP may have found the answer. Its engineers designed the recent Spectre x360 15 with a “kill switch,” mounted on the side of the laptop, that electrically disables the webcam. Here’s the kicker: if you open Windows 10’s Device Manager while flipping the switch, the webcam physically disappears from the list of available Windows devices. It’s simply not available to the OS.

That’s pretty convincing. Note that HP’s kill switch disables only the webcam, not the mic. But it seems trivial to extend that capability to the mic in a future revision.

Mark Hachman / IDG HP’s kill switch, shown here on the side of the Spectre x360 15, electrically disables the Webcam.

Other laptop makers may have their own solutions soon. Rahul Tikoo, vice president and general manager of commercial mobility products at Dell, told me that solving the privacy issues with the mic is something that Dell is looking into as a “focus area” for next-generation products. Today, Dell laptops like the Latitude 7400 2-in-1 include a function key to disable the mic, though it doesn’t disappear from the Device Manager as HP’s laptop webcam does. (Anecdotally, it seems more business laptops than consumer notebooks are at least considering the mic privacy issue.)

Lenovo acknowledged that while its Smart Display and Smart Clock contain physical switches that disconnect the microphone, its laptops do not, save for a function key that disables the mic. ThinkPad laptop mics can also be disabled in the BIOS, “but not on the fly,” a spokesman said via email. The issue is sensitive enough, however, that Lenovo has designed customer-specific Lenovo laptops that physically have neither a webcam nor a mic.

HP’s Elitebook commercial line includes a function key that disables the mic, including an indicator light to show that it’s toggled off, a company spokeswoman said. “Additionally, given our leadership in security, we are always looking at ways to improve upon these privacy tools and their implementation in the future,” she added.

If microphone privacy hasn't been a concern of yours up to now, here's a way to imagine the risk. The next time you’re in a coffee shop, coworking space, or other locale where laptops and their owners congregate, simply close your eyes and listen to all of the conversations taking place around you. Now, imagine that a hacker is doing the same thing: listening, filtering, transcribing, archiving, and correlating. If we worry about smart speakers listening in, how are a PC's microphones any different?