[HN Gopher] Falsehoods programmers believe about Biometrics
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Falsehoods programmers believe about Biometrics
Author : edent
Score : 76 points
Date : 2021-01-09 13:02 UTC (9 hours ago)
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| VLM wrote:
| One missed in the list is the seller / marketer always
| hyperinflates the equivalent bits strength of a biometric under
| the most ideal conditions etc.
|
| In real world practice the equivalent number of bits of something
| like a real world iris scanner is NOT even close to the number of
| megapixels in the camera LOL.
|
| Another problem alluded to was filth. The fingerprint scanner at
| a former employer was filthy beyond all recognition after
| housekeeping destroyed the first one trying to clean it (side
| issue, why are all biometric sensors so incredibly non-robust
| compared to a RFID scanner or human guard?). Anyway the thick
| gross layer of human grease on the fingerprint scanner made
| people grossed out during flu season so they would capacitive
| couple getting close to but not touching the sensor and relying
| on the last person to touch the filthy thing to have left enough
| fingerprint to work. It worked pretty well. The concept of a non-
| contact fingerprint scanner in the last century is pretty funny.
| I wonder if it still works. A more general filth problem is in
| the covid era I would not want to share eyeball juice with
| everyone going thru a retina scanner.
| mojuba wrote:
| Pro musicians have a big problem with their fingerprints. The
| scanners often have trouble picking up e.g. a pro pianist's or a
| guitar player's fingerprints, or even when they do, they'll fail
| to identify it days or weeks later.
| cjnicholls wrote:
| This is a more extensive list of falsehoods i usually use.
|
| https://github.com/kdeldycke/awesome-falsehood
| kdeldycke wrote:
| Just added that article to the collection:
| https://github.com/kdeldycke/awesome-falsehood/commit/eadea6...
| [deleted]
| ulucs wrote:
| How probable is it that my fingerprint matches with someone
| else's, given that there is some acceptable variance allowing my
| fingerprints to work every time?
| fundamental wrote:
| It all depends on a given implementation's choice of a
| threshold to use. Two objects will give a score which indicates
| similarity/dissimilarity and then some further logic needs to
| say if that score is good enough for a match. Some NIST
| certifications for instance end up placing requirements with
| false-match-rates at 1/10,000 (e.g. one left index finger
| matching someone else's left index finger at that frequency
| when trying a lot of random pairs).
| PragmaticPulp wrote:
| Depends entirely on the implementation, of course, but modern
| implementations have extremely low probabilities of false
| matches.
|
| These are tested by running the algorithm against large
| databases of fingerprints and looking for false matches between
| any two different fingerprints.
|
| Note that this scenario is vastly worse than any real-world
| scenario, as you can't simply have a million different people
| try to unlock a device.
|
| The practical question is to consider the probability of a
| specific random person being able to unlock your phone, which
| is orders of magnitude lower probability than considering if
| _any_ person can unlock your phone.
|
| Any secure fingerprint system would also have exponential back
| off for excessive tries, further limiting the practicality of a
| random attacker matching.
| dariusj18 wrote:
| Reminds me of when I was a kid. We left the grocery store,
| unlocked the car with a keyless remote and got in. My dad put
| the key in the ignition and couldn't turn the car on. He was
| confused, I was confused, I had felt a general sense of
| wrongness. Looked around and noticed, this wasn't our car.
| Same Make, Model, Year and Color and the keyless also
| matched, though the interior color was different. Our car was
| two cars further down the aisle. The chances of that
| happening are so very slim, but also not.
| Brian-Puccio wrote:
| Same with a mid-90s Audi with my grandmother picking up
| someone from the airport. Took us a minute to figure out we
| weren't in her car because both were immaculate inside.
| Though it was a while ago so I'm thinking they both just
| shared the same physical key to unlock the doors and start
| the engine.
| hansvm wrote:
| For a long time (maybe still?) it was common for police
| forces to buy cars which were keyed alike. What happened
| when those cars were gradually replaced? Well, the new cars
| had to be keyed to match the old ones, and taxis or anyone
| else in the market for old police cars would unwittingly be
| able to unlock the entire police fleet.
| est31 wrote:
| Just a few weeks ago the German government introduced the
| requirement to upload fingerprints to national ID cards... Quite
| sad.
| dane-pgp wrote:
| "Germany to require fingerprints and biometric images for ...
| passports and national IDs"
|
| https://www.biometricupdate.com/202011/germany-to-require-fi...
| wtmt wrote:
| I thought this would be a great list to share, but found it quite
| short and wanting in certain respects.
|
| I don't know what class of programmers this list is intended for,
| but I believe that anything about biometrics should start with
| the statement that biometrics capture and verification are all
| about probabilities and thresholds for false positives/false
| negatives. They're not deterministic.
|
| This list doesn't comprehensively cover the falsehood that
| biometrics are considered by many systems to be static throughout
| one's life. Biometrics change with working conditions, age,
| health conditions, weather and environmental factors, due to
| accidents, surgeries, etc. The "Biometrics can't be changed"
| section could do with more information.
| geoah wrote:
| The article for me is missing the rationale behind those claims.
| I am not sure programmers believe those things. I would expect
| each of these claims to have at least one story/link backing them
| up.
|
| I'm not sure any programmer claims that biometrics are the
| "perfect security measure", and if they did it would be nice to
| have a source.
| Igelau wrote:
| > a family with a genetic mutation which means they have no
| fingerprints
|
| I had to give ink fingerprints a few years back and the ah, Print
| Taker Person expressed some concern that my prints were on the
| border of not being visible enough (I have a heck of a time with
| the fingerprint doodad on my Mac). When I was recounting the
| incident to my grandmother, she said the same thing happened to
| her mother when they immigrated. It's not that I have no
| fingerprints, but they are very faint and partial.
| xoa wrote:
| Pretty meh piece. This isn't so much "falsehoods programmers
| believe about Biometrics" as it is "strawmen and tired memes
| 'techies' toss around about Biometrics". And sure enough at the
| end, the idiotic "biometrics are usernames" thing comes out. No,
| they're not usernames, nor are they passwords. They're
| measurements, any measurements, of our bodies. Hence bio
| _METRICS_. They can be fingerprints sure (one of the oldest
| ones), but they can also be anything from faces and retina to the
| musculature of your ass or skeletal structure, your gait as you
| walk or patterns in how you type. Biometrics are a rapidly
| advancing but still fairly primitive field, but anything about
| someone 's body that reasonably reliable bits of entropy can be
| extracted from can be part of an overall biometric pattern. Like
| ALL security, they are part of an economic equation as well as
| arms race in terms of how much time/resources attackers must
| expend vs how much users must expend and the value of attack.
|
| They're not silver bullets, but neither is anything else by
| definition. They can absolutely be an extremely useful part of a
| secure system for multiple reasons. Amongst them, two big ones
| are usability and threat model match. First, security systems are
| designed for and must be usable by some set of human beings at a
| practical level. The amount of time/resources the defenders need
| to expend has to be feasible and proportional. If that isn't the
| case then you simply end up with people working around it, the
| classic passwords-on-sticky-notes or add-one-each-required-
| rotation or whatever issues. Telling everyone they have to
| memorize 256 bits of entropy and then rotate it every 6 months
| and then having that fail to happen isn't a failure of the users,
| it's a failure of the security system because it's a shitty
| fucking system. Biometrics, properly done (like anything else),
| offer a significant number of bits that require a different
| attacker model to copy at high ease of use to the majority of
| users. The ratios alone make it worthy of consideration.
|
| Second, they flat out are _better_ against certain common threat
| models. Like this bit at the end:
|
| _If you think an enemy state is going to devote considerable
| resources to steal copies of your biometrics, consider changing
| to a different password mechanism._
|
| If you think a state actor is after you, well you're probably
| fucked. But that aside "just universally use passwords" is WORSE
| advice. We now live in an era of near perpetual over the shoulder
| high resolution video surveillance in many public spaces, ever
| cheaper drones that can offer the same anywhere outdoors, and
| extremely hard to detect cameras that can be quickly installed
| indoors. We have good enough storage and AI analysis to handle a
| lot of simple stuff, as China is putting into practice. From a
| fundamental ML standpoint, "a human entering a pin/passcode on
| their phone, tablet or computer" is a VERY regular pattern. The
| boxes or screens for entry, the result of entry (typically a
| bunch of dots), the patterns of input, all are highly regular in
| general. In turn, I'd be genuinely surprised if state actors
| aren't already at least testing universal wide scale automated
| password harvesting. Someone enters a password in view of a
| surveillance camera, and it automatically records their key entry
| in real time and matches it to their face. In contrast, good
| biometrics require some level of individual targeting and
| resource expenditure (this is a shifting target sure, but so is
| everything else in security).
|
| I'd certainly never depend on biometrics everywhere, but
| everything in sec is about layers and matching tools to threats.
| I do try to use biometrics and HSMs whenever I'm out in public,
| along with long master passwords that I enter in more physically
| secure areas. It's irritating to see them get dismissed so
| blithely by people who should know better, rather then
| recognizing they're a work in progress along with other
| authentication.
|
| And as far as state actors or even other lesser physical
| individualized threats go, frankly normal people just don't have
| the tools right now at all unfortunately. Dealing with attacks
| like that requires higher level composite tools like coercion
| codes or automated location/use/code based device views, all
| transparently implemented across major classes of devices and
| backed up and down the stack. Biometrics have a big role to play
| in that too, but they're just primitives along with other
| authentication factors for use in more complex applications.
| IshKebab wrote:
| > Biometrics are, at best, usernames.
|
| He probably needs to add this to the list of falsehoods because a
| lot of programmers (including the author) believe this falsehood.
| Biometrics are different to usernames.
|
| If you are under the impression that they are equivalent please
| include a copy of your fingerprint in your reply, to go with your
| username!
|
| Repeat after me: Biometrics are not passwords. Biometrics are not
| usernames.
| thih9 wrote:
| I like how the article provides examples, that's what I was
| always missing in the original articles; fortunately there are
| versions with examples now, e.g.:
| https://shinesolutions.com/2018/01/08/falsehoods-programmers... .
|
| I wish there were more points though; at the moment there are
| only five, while the linked "Falsehoods Programmers Believe About
| Names" had more than 30.
| Igelau wrote:
| I saw that as a feature of the originals. Without examples, we
| had to think about them and discuss them to understand why some
| of them were false, as well as practice being open about our
| own ignorance.
| amelius wrote:
| I think most programmers are aware of these. It's lawmakers who
| need a refresher.
| corty wrote:
| Yes! But the refresher for lawmakers should be much longer, and
| e.g. include the typical error rates and what they mean.
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