Hacker News Reader

Comment by TeMPOraL | Hacker News Reader

Holy shit, you've just convinced me to reconsider having fingerprint unlocking active on my phone...

the finger has to be warm. cutting off a finger won't actually let someone have unlimited access to your device. the mugger may not understand this though...

  microwave ?

Usually the "liveness" detection on these requires blood circulation, just warming the finger isn't going to bring that back.

That's actually nonsense. You most certainly can cut off someone's finger and use it to unlock their phone. I'm not aware of any capillary scanners on phones...

http://www.androidauthority.com/how-fingerprint-scanners-wor...

TL;DR: Cheap phones use optical sensors (can be fooled by an inkjet). Older high end phones and some new ones use capacitive scanners which require the actual finger plus an equivalent capacitance which can be faked by holding the finger with your bare hands (making sure to get close to the actual finger tip). Might take a few tries but it'll work. The latest tech uses ultrasonic sensors which measure the ridges of the fingerprint incredibly accurately. Enough so that blood loss may result in failure but I doubt that any phone's sensor is going to require that level of accuracy (do you press your finger with that precise amount of pressure every time?).

Do phone scanners have that?

I don't think iPhones do. There are videos of people unlocking phones with gummy bears, and opaque fake fingerprints.

That's why I use my toe.

I'd consider that, but I doubt my cow-orkers would appreciate me taking off my shoes.

That's why I use my toe.

While I usually try to stay serious while reading HN, That statement really made me lol. I'm rooting more for Samsung's magnetic secure transmission (MST) to be more mainstream then these card replacements.

Same.

Also, my iPhone 5s seems to read my toeprint better than my fingerprint.

You guys are joking, right? Right?

I did it as a joke at first but it actually works quite well.

And now you know why fingerprints are a really bad security device.

They're fine for casual authentication, but really poor for actual security.

The bigger problem is that you only have one set of prints. If they're compromised, you can't just regenerate a new set (well, without grafts).

I know the biometrics suck, but I haven't considered casual muggers cutting fingers off before...

"Malaysia car thieves steal finger" (2005) [0]

These were not casual muggers, since they resorted to kidnapping, also keep in mind that this was done to steal a very valuable car.

With phones also now also becoming wallets, it's not outlandish to think a thief would cut off a finger.

[0] http://news.bbc.co.uk/2/hi/asia-pacific/4396831.stm

I'm way out of my league commenting on what criminals would or wouldn't do, but I don't think _casual_ muggers would resort to cutting fingers off.

More serious, organise, full time muggers might, but I would suspect those are more rare (and you're probably in a whole lot of danger with them anyway. missing digits probably isn't your biggest concern)

Who needs to cut off fingers when you've got a 3d printer?

http://www.3ders.org/articles/20140308-world-first-3d-printe...

http://openbiometrics.org/publications/arora20133D.pdf

I'm way out of my league commenting on what criminals would or wouldn't do, but I don't think _casual_ muggers would invest in custom 3d printing solutions.

Because it's faster?

That's probably why fingerprint scanning doesn't work after 48 hours of not unlocking.

Reply on news.ycombinator.com