Show HN: PanicLock – Close your MacBook lid disable TouchID –> password unlock

by seanieb • 3 months ago

265 115 3 months ago

I wrote this after the case of a Washington Post reporter, Hannah Natanson, was compelled to unlock her computer with her fingerprint. This resulted in access to her Desktop Signal on her computer, revealing sources and their conversations.

https://www.yahoo.com/news/articles/washington-post-raid-pro...

Edit: I've a lot more details about the legality and precedence on the apps landing page https://paniclock.github.io/

mrdomino-2• 3 months ago

Neat idea.

I remember way back in the day, there was some question as to the legality of compelled unlocking of devices; IIRC, it’s been deemed legal to compel a fingerprint, but illegal (under the first amendment?) to compel entry of a password—IIRC, as long as that password hasn’t been written down anywhere.

I gather this is written to that end primarily? Or is there some other goal as well?

seanieb5• 3 months ago

https://www.yahoo.com/news/articles/washington-post-raid-pro...

Edit: I've a lot more details about the legality and precedence on the apps landing page https://paniclock.github.io/

mrdomino-2• 3 months ago

Cool, thank you.

dang• 3 months ago

(I've put a copy of this text at the top of the thread, since it's standard for Show HNs to have some intro/background up there. I hope that's ok with you!)

mrheosuper• 3 months ago

Can you intentionally use the wrong finger so that it will force to enter password

xoxxala• 3 months ago

The website has some more info on the biometric vs. password debate and legal situation:

https://paniclock.github.io/

420official• 3 months ago

While it's true that the legality of law enforcement forcing passwords in unclear, courts can absolutely force you to enter a password even if it's not written down by holding you in contempt indefinitely.

xoa2• 3 months ago

courts can absolutely force you to enter a password even if it's not written down by holding you in contempt indefinitely.

This is not true outside of a narrow exception. Indeed this is the core point of the 5th Amendment, to protect you from having to be witness against yourself. It's just as binding on the judicial branch as it is on the executive. Ordinarily, a court may not compel a defendant to testify or say something that could incriminate them.

The narrow exception is the "foregone conclusion doctrine", which allows compelling testimony about specific evidence the government legally knows exists, knows the defendant controls access to, and knows is authentic. All of which has a bunch of caselaw around it. The textbook example is somebody has a device open, and an officer directly witnesses illegal material on it, but before they can seize it the person manages to turn it off and now it cannot be accessed without a password. So the government can say "we witnessed this specific illegal material, and this device is owned by the defendant and we can prove from video that they have accessed the device, and we want access to that specific material". But if you're just crossing the border with a locked device, they cannot compel the password just to search through it, or even if they're suspicious of something specific. They need actual knowledge, either through their own evidence or because the person foolishly talks and confesses something.

Otherwise they can definitely physically seize the device for a time (which could be very inconvenient/expensive depending) but that's it.

whalesalad2• 3 months ago

Take it to the logical end - you can tie up / handcuff / sedate / restrain an individual in order to get their fingerprint (or, ahem, way worse) but you cannot extract a password from someones brain.

stavros2• 3 months ago

If it's in scope to "way worse" someone to get their fingerprint, I'm sure I can be very persuasive in getting their passwords.

vunderba• 3 months ago

cannot extract a password from someones brain.

May I introduce you to XKCD Number 538.

https://xkcd.com/538

Nexxxeh2• 3 months ago

There's also the issue that the device is covered in fingerprints, and if you can build a clean image of the print, you can likely manufacture a gelatin copy of that fingerprint that will work on most fingerprint scanners.

I can't speak to the current generation of Apple fingerprint scanners, but historically iirc you can grab a print, clean it up in Photoshop, print it on OHP transparency using a laser printer and use it like a mould to copy a fingerprint.

disillusioned• 3 months ago

Aren't the current fingerprint scanners ultrasonic rather than optical? I think they rely on the actual physical ridges

iamcalledrob• 3 months ago

I wonder if the US is the only place where this applies?

The UK, I believe, can compel you to provide passwords that you would be reasonably expected to know.

FerretFred5• 3 months ago

Sadly yes. IANAL but under the Ripa Act they can issue a section 49 notice and you risk imprisonment for not complying. However, they need proper authorisation to do so, and the notice must be lawfully issued, so presumably a magistrate. This is all part of our famous British Justice!

elcritch• 3 months ago

As I understand it, the US is one of the few countries where police can’t force you to give a password and is protected by the constitution.

Looks like in the EU it varies depending on the law. But unless it’s in their constitution the laws could be changed. For example, see the current UK government trying to get rid of trial by jury for some crimes since it’s inconvenient.

ttul• 3 months ago

The 2026 version of "Boss Key".

Forgeties792• 3 months ago

PSA to iOS users: if you tap the lock button 5x it forces password-only unlocking. Useful at protests or any precarious situations with law enforcement.

chuckadams• 3 months ago

Bringing up the shutdown screen (hold lock and either volume button) will also do it.

itsdesmond2• 3 months ago

I did not know that. That is extremely convenient. Thank you.

sigio• 3 months ago

On GrapheneOS (and maybe android generic?) this calls the emergency number, I just found out (with a 5 second timer to cancel this luckily)

spockz2• 3 months ago

It is also an option in iOS under Settings -> Emergency SOS. And with it turned on it will both call emergency services and require pin for unlock.

jonpalmisc• 3 months ago

This still leaves your device in an AFU (after first unlock) state, with user data decrypted, and should not be treated as secure.

The only thing you can do (to protect your data from forensics, etc) is to return it to BFU by shutting it off.

Forgeties792• 3 months ago

Better than nothing and keeps them from having unlocked access. You can do it fast in your pocket.

seanieb5• 3 months ago

Correct. This is a classic security vs convenience tradeoff. I mention that trade off on the landing page, PanicLock vs Shutdown

Use shutdown when you can, PanicLock when you can't. Shutting down is the most secure option—but when you need your Mac locked now and you'll be back in five minutes, PanicLock is your answer.

*PanicLock* - Fast "oh shit" button - Lid closed when in transit. - Instant lock (1 second). Disables Touch ID immediately - Preserves your session - Back to work in minutes

*Full Shutdown* - Maximum security - Purges encryption keys - Fully locks FileVault - Takes time to shutdown & restart - Kills your session

ASalazarMX• 3 months ago

- TSA: Hey, bring your bag and devices here. Routine inspection.

- Traveler: [takes phone from the bin] [finds lock button] [click] [click] [click]

- TSA: Hey, stop what you're doing Mr. Terrorist!

spockz2• 3 months ago

That is why you would do it before you let your phone go out of sight. I used to even turn off my electronics to prevent damage by scanners. Now I don’t bother anymore but it could be a plausible excuse.

p0w3n3d• 3 months ago

What's the rationale? It should be described in the README.md IMO

itsdesmond2• 3 months ago

A person might use it to stop someone getting into your computer through certain types of physical coercion, forcing your finger to the reader, or (much less likely but I’m sure security services know how) a copy of your fingerprint.

But it isn’t a why, it is a what. That what is a tool that lets you quickly disable Touch ID for whatever reason you want to.

seanieb5• 3 months ago

That's good feedback. I just added it to the readme:

"PanicLock fills a gap macOS leaves open: there is no built-in way to instantly disable Touch ID when it matters. Biometrics are convenient day-to-day, and sometimes preferable when you need speed or want to avoid your password being observed. But in sensitive situations, law enforcement and border agents in many countries can compel a biometric unlock in ways they cannot with a password. PanicLock gives you a one-click menu bar button, a customizable hotkey, or an automatic lock-on-lid-close option that immediately disables Touch ID and locks your screen, restoring password-only protection without killing your session or shutting down."

I've more details on the apps landing page - paniclock.github.io

quicklywilliam• 3 months ago

Great idea and implementation! If you are hesitant to install this for any reason, you can accomplish the same thing with this one liner:

  sudo bioutil -ws -u 0; sleep 1; sudo bioutil -ws -u 1

Edit: here's a shortcut to run the above and then lock your screen. You can give it a global keyboard shortcut in the Shortcuts app. https://www.icloud.com/shortcuts/9362945d839140dbbf987e5bce9...

alin23• 3 months ago

Hook this to a lid angle below 30° trigger in https://lowtechguys.com/crank and you can easily make it run on a simple lowering of the lid

Wowfunhappy• 3 months ago

At that point, why not just disable Touch ID?

orthogonal_cube• 3 months ago

Honestly I’m surprised this wasn’t already a feature in macOS. Thank you for coding it and publishing as open-source!

freehorse2• 3 months ago

This is great. I see many times "security advice" against biometrics replacing password unlock, but most of the time I am more worried about getting recorded by somebody/something while typing a password in the open than anything else. This makes it better for those other cases.

Terr_• 3 months ago

At that point what you need is true multi-factor. For example, both fingerprint and per-device PIN.

Regrettably, that's not often offered as a feature, even when the infrastructure is already there.

akdev1l2• 3 months ago

Notably macOS cannot do this

parl_match2• 3 months ago

I've thought the Apple platform has two glaring omissions

- touchid and biometric configuration profiles (standard, paranoid, extra paranoid)

- versioning for icloud backup

The simple fact is that there is no one-sized-fits-all use case for this.

Biometrics are great for the average user! They reduce shoulder surfing and increase security.

But for some users, you might want two factor for biometrics (such as an apple watch), or short windows before password entry is forced. You might want both biometrics AND password entry required. You might want to enable biometrics only when two factor is enabled.

Look, I'm not saying that what I've said is the ideal setup, by the way. Just that there is a lot of room for improvement versus the status quo.

gruturo2• 3 months ago

This would be perfect if it could monitor the force with which the lid is closed (macs have accelerometers after all, either this info or an acceptable proxy could be derived?).

Gently close? no action.

Stronger, faster action? Disable touch ID

Slam shut in full panic? yeah disable all biometrics, lose all state, even wipe the ram and the filevault key if it's an option

QuercusMax• 3 months ago

You must not have cats or children if you think that last one is reasonable

gruturo2• 3 months ago

Ok just unload the filevault key from ram, better? And if possible tell the secure enclave to revert to the before-first-unlock state

thih9• 3 months ago

Perfect rage quitting machine. There should be an enterprise version: when lid is closed with full force it also sends a professional resignation letter to the current employer.

wolvoleo• 3 months ago

I'm surprised Apple doesn't offer an option. On the iPhone you could do this by pressing the power button several times. Not sure if this still works because the iPhone 6 was my last one though.

bhj• 3 months ago

Pressing and holding Power + Vol Up/Down is the current combo

dozerly• 3 months ago

Pressing the power button 5 times fast also does it!

nailer• 3 months ago

If someone can force you to use touch id they can probably also force you to enter your password.

(If you’re about to comment about fingerprints on transparency film and balloons filled with warm water then yes good point)

skillina• 3 months ago

Capable? Yes. Willing? I wouldn't be so sure. You don't even need to hurt someone to manhandle them enough to put their fingerprint on a scanner. Whereas forcing someone to give up a password could rise to the level of torture.

Of course, I imagine the majority of people would yield their password if you simply threatened to detain them long enough to make them miss their flight.

FerretFred5• 3 months ago

I agree.. having to spend longer than necessary at UK's Manchester Airport would have me singing like a canary!

urbandw311er• 3 months ago

I think it’s about plausible deniability: you can pretend you’ve forgotten your password, you can’t pretend you’ve forgotten your finger.

rglover• 3 months ago

This is awesome, thank you. Was just thinking about this problem the other day. Glad someone whipped something up.

surround3• 3 months ago

in sensitive situations, law enforcement and border agents in many countries can compel a biometric unlock in ways they cannot with a password.

If the threat model includes state-level actors, then disabling biometrics won't prevent data from being retrieved from physical memory. It would probably be wiser to enable disk encryption and have a panic button that powers down/hibernates the computer so that no unencrypted data remains on RAM.

The website says shutdown "takes time" and "kills your session" but a hibernation button would take effect just as fast and would preserve the session.

jovial_cavalier• 3 months ago

a cop works for "the state," but he's definitely not a "state-level actor."

surround3• 3 months ago

How do you define "state-level actor?" Police departments certainly have access to state and federal forensic resources to access unencrypted data in memory.

LoganDark• 3 months ago

Apple Silicon is at least much more difficult to attack in this way, though it might be possible.

deadbabe• 3 months ago

There should just be a way to setup an alternate dummy account based on the finger you use. This gives the illusion of compliance but your real data is safe.

armadyl2• 3 months ago

If you're in a situation where this is a pressing issue, it's not a good solution as it's trivial to detect if it's a fake environment, especially if they get suspicious and run external forensics on it.

iirc the GrapheneOS team won't implement this feature for that reason

FerretFred5• 3 months ago

The middle finger could be the emergency use one ...

moralestapia• 3 months ago

This should be an OS X feature, it's just that good.

Great work, congrats!

momentmaker• 3 months ago

The iOS equivalent is to hold the side + volume button until the power slider shows up. Cancel out of it and the next unlock will require your passcode. Pressing the side button 5x triggers Emergency SOS which does the same thing. Been there forever but barely anyone knows about it.

Nice to see something like this on the Mac side.

tverbeure• 3 months ago

Or IMO easier: press the on/off button 5 or more times in rapid succession.

joombaga• 3 months ago

WARNING: This triggers an emergency call on Android.

armadyl2• 3 months ago

How beneficial is this versus just being theater? The example used in this is the government accessing the reporters laptop via biometrics.

But in this case, and especially under this admin legal or not this app won't stop them, unless I'm misunderstanding the macOS security model. Even with FDE enabled, sending it to the lock screen with biometrics disabled will not do anything to stop them from being able to access the contents of the hard drive via forensic methods with relative ease.

I think that at best this will only stop the casual person (i.e. a family member or roommate/random snooper)? In which case there would be no point to switch away from biometrics.

You're far better off just keeping more private information on the iPhone and isolating that data from a Mac, since that has far more resistance to intrusion in AFU mode than a Mac.

gh02t• 3 months ago

My interpretation was that it's easier to physically force someone to mash their finger on the sensor than to get them to divulge a password, not that it offers you any kind of legal protection. But yeah, it's a plausible but somewhat contrived situation to find yourself in.

nofriend• 3 months ago

It does offer you legal protection. In the US, the right to not self incriminate protect you from divulging passwords but does not protect you from giving up biometrics. In other countries the rule is different.

FerretFred5• 3 months ago

I'm reading this nervously on my MacBook Air, but chuckling quietly with my cheapest Mac Neo (my new travel companion).

october8140• 3 months ago

If this were a concern for me the better choice is shutting down the laptop to encrypt the drive and disable biometrics. This does nothing since the drive is still unencrypted.

dddddaviddddd• 3 months ago

This does nothing since the drive is still unencrypted.

Even though the data is unencrypted in memory, an attacker would still need either a local privilege escalation (from the login window?), or some sort of side-channel attack if they're still not able to get the password.

lxgr• 3 months ago

What do you mean by “the drive is still unencrypted”?

If your threat scenario includes somebody performing a DRAM freezing attack or similar, these are orders of magnitude harder to pull off successfully than to compel or bypass a biometric sensor, especially when the device is covered in the owners fingerprints.

VectorLock• 3 months ago

Can you get TouchID to register multiple fingers and script the actions; maybe your middle finger unlocks touchID, but your index finger disables touchID until you enter your password.

aequitas• 3 months ago

You can have different fingers registered to different accounts. I used it to 'fast user switch' between accounts.

HNisCIS• 3 months ago

Why not just disable touchID if the Bluetooth modem hears advertising packets from the 00:25:DF OUI?

Kwpolska• 3 months ago

No command injection — Timeout parameter is a Swift Int, not a string

Please don't use slop machines to write READMEs. If you're launching bioutil as a subprocess, you're passing the timeout as a string. In your code, you read the timeout, convert to int, set timeout to 1, and set it back to the previously retrieved value. There is no difference between keeping it as strings or doing a string->int->string round-trip, assuming no sizing and formatting weirdness.

seanieb5• 3 months ago

This comment is based on one of my commits. The round-trip through Int is exactly what makes it safe.Int(value) will return nil (and be rejected) for anything that isn't a valid integer. no ; rm -rf /, no shell. String(seconds) on a Swift Int can only ever produce a decimal number. (which is probably overkill and not needed in this context.) > Please don't use slop machines to write READMEs. Trust me, they do a better job than I ever will.

Having said all that, it's probably something that could be dropped from the readme. I'll edit now.

edit: updated the readme. Thanks for taking the time to proof read it.

dilberx• 3 months ago

very nice thought

wodenokoto• 3 months ago

Maybe clicking the Touch ID button could invalidate the login attempt and ask for password?

I like logging in with my finger print, but I would like an “out” in the same vein as this.

tpetry2• 3 months ago

I would love to have a mode that I must use my long password to unlock my mac for security purposes. But when unlocked, use touchid as an alternative to my password for convenience.

So just the normal TouchID mode but not for unlocking the mac.

traceroute665• 3 months ago

So just the normal TouchID mode but not for unlocking the mac.

Erm ? Just go to System Preferences and turn off "Use Touch ID to unlock your Mac" ??

tpetry2• 3 months ago

When you disable that, its also disabled for sudo operations when unlocked. it basically disables TouchID completely.

onchainintel• 3 months ago

This is dope OP, well done. Terrific solution on something that Apple clearly missed.

grishka• 3 months ago

This makes me wonder how I can do the reverse — I'd like to always use touch ID and never ever be asked for password except when it's technically necessary, e.g. after a reboot. In effect, I'd like to completely remove this time component from biometric authentication.

Wingman4l7• 3 months ago

An opportune time to mention the real-world example of when the authorities really wanted to gain full access to a computer but did not want to resort to legal compulsion or "rubber-hose cryptanalysis" -- they simply waited until the target was logged in, staged an altercation in the immediate vicinity, and then snatched the open laptop away from them.

You can read about the sting, here: "How Did Investigators Catch the Dread Pirate Roberts (DPR) in San Francisco?" https://www.forensicscolleges.com/blog/forensics-casefile/si...

deadeye2• 3 months ago

INAL, but if the authorities had captured your device with touchID enabled and legally ask you to use it to login and you do an action that would disable touchID, then that would be "obstruction".

antiframe• 3 months ago

That's the point of this. TouchID is no longer enabled. Someone unknown party approaches you, you close your lid (disabling TouchID). Then they "legally" ask you to put your finger on the sensor. You do. They didn't ask you before you close your lid.

You're thinking more along the lines that they ask you to touch the sensor and you use your fingernail razor blades to damage the sensor or something like that.

deadeye2• 3 months ago

Yes, I meant to respond to other comments in here directly, but got messed up.

Others had floated the idea of locking by using an alternate finger with touchID, after the fact.

squibonpig• 3 months ago

That’s not just one leak investigation—it’s access to a reporter’s complete source network, enabled by biometric convenience features.

Really nice to see that everything is AI generated now!

scoofy• 3 months ago

I think the thing that really surprises me is that Washington Post reporters are using Apple products and not just a Linux distribution. They are professionals. At some point, Apple can be compelled to work against you, but Linux is just a product off the shelf.

saadn92• 3 months ago

What's the timing like between the lid sensor firing and sleep actually kicking in on Apple Silicon? I ship a couple menu bar apps on M2 and listening for NSWorkspaceWillSleepNotification feels like you get maybe 200ms before the system is gone. If disabling TouchID requires a round trip to the secure enclave in that window that seems like it'd be a race.

bradknowles• 3 months ago

It’s easy enough to just configure TouchID so that it doesn’t work to log into your computer. It’s only used for authorization to do certain operations (like ApplePay), once you have logged on with a password.

I do this on all my devices. And I don’t use FaceID for anything at all. Which makes modern iPhones a bit of a pain, but I do it anyway.

Show HN: PanicLock – Close your MacBook lid disable TouchID –> password unlock

Related Stories