Phones should have a 'guest lock' feature | Hacker News Reader

Phones should have a 'guest lock' feature

curvise.net

41 pointscrisdias55 comments

Both Apple and Android have this feature preloaded. On Apple it’s called Guided Access and is three taps of the power button if enabled. On Android I’m not sure but I do know it exists (edit: it’s called App Pinning)

On iOS you can also disable specific actions and even select areas of the screen you want to disable touchscreen usage over.

100% - I would have assumed the author would have searched first as it's trivial to find this feature if you look on Google or ask ChatGPT.

I do wonder if part of the issue though is that we have thousands of these 'great' features, so discovery is poor because people can't possibly know about them all. 'great' features lost in a sea of other 'great' features.

well this is embarrassing. just noticed a ~1000% increase in traffic and it's almost all from hackernews where i find the post getting dunked on :)

anyway, at least a few dozen other people didn't know about this feature, so i guess the post was helpful anyway. for the record, just now i tried and couldn't find any reference to these modes in the first 2 queries i thought of, so it's not trivial to find that it already exists (although i do not use google or chatgpt). i just assumed that if the feature existed i would have heard about it before, so i wrote a blog post, and it was fun.

to your point about discoverability, i think that's true, and there's no comprehensive user manual for android, which would be the normal way one would discover features in a device. hm, that's another feature i'd like in my phone: a built-in digital technical manual, like the safety & regulatory manual.

Beware of trying it when you really might need your phone. It can get stuck in weird ways where triple-clicking brings up the pin entry screen and then shuts off the display for a while being unresponsive to the power button. Basically it’s frustratingly buggy.

Guided Access is what I occasionally used when our first child was 2-3 years old and I had to hand him the phone to watch videos with input locked out. It was never an effortless process, it would be awkward to fumble around with before handing my phone to someone. It would make it look like I have something to hide (don't we all?) Maybe I'm doing something wrong.

> On Apple it’s called Guided Access and is three taps of the power button if enabled.

Nice. Unfortunately, GA does not seem to work with Apple Wallet at all.

It should work. If you mean using Guided Access while Apple Wallet is enabled, you double click for Apple Wallet and triple click for Guided Access. If you want to use Apple Wallet while Guided Access is enabled, you have to enable the side button in Guided Access settings.

You can also configure the action button to enable Guided Access as well depending on what phone you have.

> If you want to use Apple Wallet while Guided Access is enabled, you have to enable the side button in Guided Access settings.

I don't have that one (iPhone 15 Pro). When triple tapping in Wallet, I get an overlay "guided access cannot be opened when multiple apps are active".

The scenario would be e.g. at a concert entrance queue where there is a nonzero risk of someone snatching the unlocked phone out of my hands.

I've just tested it and it works - you have to disable touch though to get the full 'lock down to one event ticket'

From the post "There's a better name for it somewhere but it's not my job to find it"

You think if they couldn't even be arsed to google the name, that they'd google to find out their idea has already existed for years?

Geez-sus

Maybe I’m reading too much into these negative comments, but we’re reading the same text. Right? Some rando’s thoughts in their public blog (no offense intended; the about admits they’re just a person on Central Time)?

It’s not like this is an article on Tom’s Hardware or TechDirt. I’m not against pointing out errors and oversights, but why this sense of offense, shock, incredulity.

Heck. It’s not AI Slop or do you want more AI articles instead of these uninformed hot-take blog posts? Hehe

For me, it's that writing the blog post clearly took more effort than searching for the proper name of the feature. So writing in the blog post that they can't be bothered to find the proper name of the feature seems performative: if they were actually concerned about addressing the problem, they would have addressed it, and there would be no blog post.

I'm confused about what "bothered to find the proper name" means for a feature they believe they're inventing. If they believed it had a name that would mean they already know it exists.

Maybe I overestimate people if I assume that when someone thinks of something they want to do with their phone, they google how to do it, rather than just assume they invented it and write a blog post about it

I believe this works on Android in general, but I tried on GrapheneOS. Open the Settings app. Tap Security & Privacy > More security & privacy > App pinning. After that is enabled, if you want to pin an app, open it, swipe up into the recent-apps view, tap the icon of the app above the preview pane, and select "Pin".

The feature is buried a bit. I believe this is because it's more of a best-effort protection. The settings page itself says:

"When an app is pinned, the pinned app may open other apps and personal data may be accessible. If you want to securely share your device with someone, try using a guest user instead."

Due to the intent system on Android allowing a pinned application to open another one (for example by sharing something), I prefer instead to create a guest user and add the app in question to that account.

That way no other applications are available to open, accidentally or otherwise.

> Due to the intent system on Android allowing a pinned application to open another one (for example by sharing something),

I tested it and it blocks opening other apps when pinned. Maybe blocking app opening doesn't work for apps using some older system APIs.

I don't understand why this isn't activated by default. It just adds an extra "pin" option when you tap the app icon.

It's the kind of feature that would rub people the wrong way, whether it's a cop, a friend, or a stranger you want to show a funny video to.

To give a couple of examples, using this would be a bit like locking the glove box in front of traffic cops, or going around the house locking rooms when you have a guest.

The only way to make it socially acceptable would be to make it some sort of default (for example, requiring face id when switching apps, with pin/fingerprint as a backup), which will probably be an option as the lag and failure rate of face id or other owner-detection technologies improve.

> To give a couple of examples, using this would be a bit like locking the glove box in front of traffic cops, or going around the house locking rooms when you have a guest.

That's a good point. Doing this basically says "I distrust you", which you probably don't want to say. (At least I don't.)

In the case of cops there's basically no way to interact with them that's both safe and makes them happy. But I just keep a printed version of my insurance for that reason.

This feels like a social problem, not a technological one, and I am unconvinced that a technological solution will work here.

If the worry is that the cop you hand your phone to will take more access than you want, then attempting to limit that access is probably not going to work out the way you want.

A more effective solution would be better legal protections.

Technical protection >> Law, the law is too easliy broken

Technical protections don't work on people willing to break the law [1].

[1] https://xkcd.com/538/

The wrench attack is already illegal under the law

True, but it's clearly and explicitly illegal, which means that the bad thing still happens but there's potential for justice. Technical solutions don't give that.

Well, iOS does already. „Guided Access“ is exactly what you described.

Unless I'm misunderstanding, isn't that what app pinning on android is?

https://support.google.com/android/answer/9455138?hl=en

I had an Android phone circa 2018 (Samsung S8) that had this feature: it was called "App Pinning" and people could only navigate inside the pinned app until you unlocked your phone like you usually would.

Edit: I am now an iOS user since 2022, and I only learn about "Guided Access" from other comments haha

How about a guest unlock where you can lend your phone to someone to do basic web browsing or make a call, but they can’t see any of your data.

We could call it RMS mode.

in RMS mode you would also share the source of all the apps the guest might be using.

android has a guest mode

> This means it would be more easily abused if you're using biometric unlocks, yes, but by no means does it make the feature useless. And it normalizes a level of trust between individuals which is appropriate, but impossible, in many situations.

Here's the problem. By being abusable, it falsly normalises a level of trust. I.e. it deceives the user into trusting it.

The feature I want most is NOT sending a notification to the app whenever I take a goddamn screenshot.

> Android and iOS should have a system-level ability to lock focus on the active application.

iOS already has this, it's called Guided Access and you can access it by triple-pressing the power button... it even lets you set up areas of the screen that can't be pressed.

App pinning exists on Android already, it's extremely useful if you're handing over your phone to your child to just watch netflix or whatever :P It's just extremely unintuitive, I had to google where it is.

This is a silly article. Both Android and iOS have exactly this feature.

in response the all the comments that state that this feature already exists. i didn't know about that, and it's also not the kind of feature that should be obvious so i would not think to search for it, so i am very glad to find this here.

needing this happens rarely and in most cases where i needed it i actually wanted to show a static screen and not even give access to the whole app. for that i found an app that can show an image on an otherwise locked screen.

I need this for when my child gets a hold of the phone.

How so? You cannot engage the mode once child has phone.

App pinning is a thing on Android already, although I don't know how well it's supported in all the devices.

Entirely logical, but phones seem designed to be tracking/surveillance devices.

Why are you handing your phone to police? Why are they even asking for it?

Because you need to prove you have insurance to drive and the proof is on your phone rather than a piece of paper.

I don't know about America but in the UK, if you can't provide proof immediately the officer will give you a "producer", which is a legal notice requiring you to provide the evidence at a police station within some time limit (typically a week or two).

Edited to add: I'd guess this is less common these days because the British police have access to a database of motor insurance anyway.

I've never had to show proof of insurance here, in the Netherlands, it's linked digitally to your license plate. I don't understand why other countries wouldn't do the same.

iOS has a hidden album but the UX isn't great: https://support.apple.com/en-us/104987

GrapheneOS has this.

"Android and iOS should have a system-level ability to lock focus on the active application. This would mean you could open a concert ticket, a photo, or your digital insurance record (which is a VERY BAD IDEA to hand to a cop without this feature), guest-lock your phone, and hand it over without any worry that someone could start opening other apps to look for things you didn't want to show them."

I think this already exists in iOS and is called "Guided Access"? https://support.apple.com/en-us/111795

Samsung has had this for about ten years now. Switch to the app switch view, hold the icon at the top and pin the app. If I remember correctly, on some versions this had to be enabled once in settings.

> or your digital insurance record (which is a VERY BAD IDEA to hand to a cop without this feature)

Not just because of the privacy aspects, but what if you're already using your phone to record the interaction?

yeah, handing your unlocked phone to a flight attendant during boarding or an immigration official while entering a country has become commonplace too.

In the UK, presenting a ticket to a humam often leads to this for them to scroll it. First ensuring the QR code is visible does not always suffice.

This is pretty much what app pinning already does on Android, though with caveats such as the pinned app being able to launch other apps.

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