Speaker 1: Get in touch with technology with text Stuff from how
Speaker 1: Stuff Work dot com. Either everyone, and welcome to Text Stuff.
Speaker 1: I'm Jonathan Strickland and I'm La. And you know, we
Speaker 1: had to actually verify our identities before walking into the podcast,
Speaker 1: which is just standard operating procedure here in How Stuff Works.
Speaker 1: Oh right, it's a it's a blood sample, retina scan,
Speaker 1: and fingerprint before we're allowed to enter any doors. Yeah,
Speaker 1: it's really awkward. That's why most of us no longer
Speaker 1: wait till the last minute to have to run to
Speaker 1: the bathroom because disaster can strike. But it does mean
Speaker 1: that we thought, hey, we should talk about biometrics, and
Speaker 1: then we started looking into it and getting really excited,
Speaker 1: and then we realized, hey, there's a lot to talk about, right. Biometrics,
Speaker 1: of course, being the measurable biological or behavioral characteristics used
Speaker 1: for for any given individual. Yes, this is what how
Speaker 1: the FBI says, this is what the biometrics are. So, uh,
Speaker 1: you know, it's one of those things where we knew
Speaker 1: it was a huge topic and we decided to narrow
Speaker 1: it down. So today we're specifically focusing on your fingerprints,
Speaker 1: well not your fingerprints, I mean, I mean everyone's fingerprints. No,
Speaker 1: see the person sitting next to you, No, not that one,
Speaker 1: the other one, that person's fingerprints. That's that's the one
Speaker 1: we're concentrating on. So yeah, because everyone has has different fingerprints,
Speaker 1: I mean like everyone, right, And this is something that
Speaker 1: has been known for a while but then forgotten and
Speaker 1: then rediscovered. So we're going to talk about that because
Speaker 1: it's kind of funny. So these days we think of
Speaker 1: biometrics as sort of those automated ways to verify your
Speaker 1: identity based on some sort of biological characteristic, like you know,
Speaker 1: the eye scan or the fingerprints scan or whatever. Vocal
Speaker 1: scans as well, you know, like the voice imprint. Lots
Speaker 1: of different Hollywood versions of this. But you know, again,
Speaker 1: going into that fingerprint approach, we thought that, you know,
Speaker 1: we we look at not just how we've defined it
Speaker 1: and how stuff works, but look at a whole history
Speaker 1: of fingerprinting. U We're not the first podcast to do this,
Speaker 1: by the way, certainly not. Josh and Check of Stuff
Speaker 1: you Should Know did an episode on April called how
Speaker 1: Fingerprinting Works, and they go pretty deeply into the history
Speaker 1: and say many pithy things. So if you would like
Speaker 1: to check that episode out. You can go to Stuff
Speaker 1: you Should Know dot com right and just stick around
Speaker 1: because we're gonna say some pithy things too. We are
Speaker 1: going to cover some of the history, kind of a
Speaker 1: quick overview. But first I thought I would read a
Speaker 1: couple of little excerpts from our article on how fingerprint
Speaker 1: scanners work, because there are a couple that I thought
Speaker 1: were really interesting from how stuff Works dot Com. Neither
Speaker 1: of us actually wrote this. Nope, Nope, I didn't write
Speaker 1: this one. This one says people have tiny ridges of
Speaker 1: skin on their fingers because this particular adaptation was extremely
Speaker 1: advantageous to the ancestors of the human species. The pattern
Speaker 1: of ridges and valleys on fingers make it easier for
Speaker 1: the ends to grip things in the same way a
Speaker 1: rubber tread pattern helps to attire grip the road. The
Speaker 1: other function of fingerprints is a total coincidence. Like everything
Speaker 1: in the human body, these ridges form through a combination
Speaker 1: of genetic and environmental factors. The genetic code and DNA
Speaker 1: gives general orders in the way skin should form in
Speaker 1: the developing fetus, but the specific way it forms is
Speaker 1: a result of random events. The exact position of the
Speaker 1: fetus in the womb at a particular moment, and the
Speaker 1: exact composition and density of surrounding amniotic fluid decides how
Speaker 1: every individual ridge will form. This, by the way, is
Speaker 1: how identical twins can have different fingerprints. Pretty cool because
Speaker 1: you know, genetically they're identical, but their fingerprints are different,
Speaker 1: still different. Interesting. So looking at this history, you might think, Okay,
Speaker 1: I've heard about fingerprinting, particularly when it applies to law enforcement.
Speaker 1: That's probably where a lot of people are familiar with it.
Speaker 1: Besides the verification. Sure, sure, and uh and a couple
Speaker 1: popular media pieces have talked recently about Um. I mean
Speaker 1: you you get things like Ripper Street or Sleepy Hollow
Speaker 1: having characters going like this new fingerprinting thing in the amazing,
Speaker 1: amazing age of Victoria. Um, not not so much. Actually,
Speaker 1: so fingerprints people, Well, first of all, people have been
Speaker 1: aware of them for ages because we're curious folks, you know,
Speaker 1: human beings. We we were very curious and narcissistic. We
Speaker 1: like to learn stuff, and we like to look at ourselves.
Speaker 1: And how do I know that this dates back? Are
Speaker 1: ages and ages and ages ago because we have prehistoric
Speaker 1: depictions found in Nova Scotia uh, and it depicted a
Speaker 1: hand with ridge patterns on the skin. Now, that does
Speaker 1: not mean that the ancient Nova Scotians were familiar with
Speaker 1: the fact that all the fingerprints were unique and therefore
Speaker 1: no two individuals had the same ones, but at least
Speaker 1: show that, you know, yeah, they noticed them. Yeah, but
Speaker 1: the ancient Babylonians may have actually used ping of prints
Speaker 1: to differentiate people. Um, we've found fingerprints in clay to
Speaker 1: to sign business transactions, and the ancient Chinese used inked
Speaker 1: fingerprints for both business purposes and child identification. And in
Speaker 1: the thirteen hundreds in Persia, official government documents often included fingerprints,
Speaker 1: probably to indicate they were authorized and official. Now, according
Speaker 1: to the US Marshall's Office, which has an entire web
Speaker 1: page devoted to fingerprinting in the history of it, one
Speaker 1: government official in Persia at that time made the observation
Speaker 1: that no two fingerprints were alike, which obviously would be
Speaker 1: very important if you're making a document official or authorized.
Speaker 1: But it wasn't until the eighteen eighties that that amazing
Speaker 1: Age of Victoria previously mentioned that we got some kind
Speaker 1: of official classification system, right. It wasn't until the modern
Speaker 1: era that we started seeing it in UH story. It
Speaker 1: wasn't even in wide use at the beginning. It was
Speaker 1: just kind of exploratory. Dr. Henry Faulds back in eighteen
Speaker 1: eighty posed using fingerprints for identification as well as a
Speaker 1: means of classifying them. So he forwarded these ideas to
Speaker 1: a certain Charles Darwin, very important historical figure in his
Speaker 1: own right. But Darwin at the time was towards the
Speaker 1: end of his life and felt that he did not
Speaker 1: have the necessary UH time and energy to devote to
Speaker 1: this thought. It was really interesting, however, so he forwarded
Speaker 1: the information along to a cousin of his named Francis Galton.
Speaker 1: So false would write a scientific paper about his methods
Speaker 1: and actually identified a fingerprint. Ascertain the identity of the
Speaker 1: person who left that fingerprint on bottle of alcohol shouldn't
Speaker 1: come as any surprise. I guess who brings it all together?
Speaker 1: It does. Then in three Mark Twain would would use
Speaker 1: this this new startling scientific information in a story. Yeah,
Speaker 1: it was in Life on the Mississippi, and in that
Speaker 1: one of the elements of that stories of order is
Speaker 1: identified through the use of fingerprints. And he would revisit
Speaker 1: the idea in a book called Putting Head Wilson. Putting
Speaker 1: Head Wilson. Yea, so it's interesting. Now this was before
Speaker 1: anyone was actually using uh, fingerprints in any kind of
Speaker 1: criminal investigations on an official basis. It had not been
Speaker 1: science fiction, really was it kind of was so so
Speaker 1: that was exciting. But but soon in eighteen eighty eight,
Speaker 1: Sir Francis Galton, remember the cousin to Charles Darwin, who
Speaker 1: had received information about this about ten years previous, um
Speaker 1: began his own study of fingerprints. Yep. He wrote a
Speaker 1: book in eighteen ninety two and put forth a formal
Speaker 1: classification system and identify the tiny characteristics used to differentiate fingerprints,
Speaker 1: which now we call Galton's details. He also observed that
Speaker 1: fingerprints don't change over the lifetime of a person, so
Speaker 1: the ones you have when you're a kid are the
Speaker 1: same ones you have when you're old. Originally wanted to
Speaker 1: kind of link fingerprints to certain types of traits like
Speaker 1: intelligence or heredity, which is so racist. Yeah, kind of essentially,
Speaker 1: I think this was almost in an attempt. And I
Speaker 1: don't know enough about Galton to say this for sure,
Speaker 1: but it seems like an attempt to justify certain society's
Speaker 1: beliefs in certain people, that kind of thing. Yeah, it
Speaker 1: wasn't necessarily so racist, but um, but it's kind of
Speaker 1: it kind of runs in that direction. Yeah, because I mean,
Speaker 1: the idea that you could identify a person's intelligence based
Speaker 1: on their fingerprints already seems a little sketchy, And in fact,
Speaker 1: he did determined that there was no connection. There was
Speaker 1: no there were no identifier marks in a person's fingerprints
Speaker 1: that would give you any clue as to that person's
Speaker 1: intelligence or genetic background. However, he did figure out that
Speaker 1: there were a lot of differences and that people didn't
Speaker 1: weren't likely to have the same fingerprints. Yeah, unlikely, in
Speaker 1: the order of one in sixty four billion, that's pretty unlikely.
Speaker 1: So in eight we get the first use of fingerprints
Speaker 1: in a criminal investigation on an official level. Uh one vs.
Speaker 1: Tech And I'm sure I butchered his last name. Who
Speaker 1: was a police officer in Argentina used them in a
Speaker 1: murder investigation. It was actually a really tragic case, but
Speaker 1: the discovery meant that he was able to solve this
Speaker 1: mystery and prove that the person that was believed to
Speaker 1: have been the murderer was in fact not the killer.
Speaker 1: So Uh, not only was it the first use, but
Speaker 1: it was a pretty dramatic example of it. Now, between
Speaker 1: we're gonna skip to nineteen eighteen, but between the late
Speaker 1: nineteenth century and the early twentieth century he started to
Speaker 1: see fingerprints get adopted into various legal organizations all around
Speaker 1: the world. The United Kingdom and the United States were
Speaker 1: leading the way, but it was all over the place.
Speaker 1: So by nineteen eighteen you have Edmund Lekard who says
Speaker 1: that you only need twelve points of similarity between an
Speaker 1: individual's fingerprint and a target fingerprint to serve as a
Speaker 1: positive identification. Now you may have heard about those twelve
Speaker 1: points of singularity, that this is somehow like a legal thing,
Speaker 1: that if you were able to meet those twelve points
Speaker 1: of singularity, you have the legal basis to say this
Speaker 1: person did this. Uh, not necessarily a legal definition at all.
Speaker 1: In fact, UH, countries have very very different ways of
Speaker 1: saying whether or not a fingerprint is a valid match
Speaker 1: for another one, and some, like the United States, do
Speaker 1: not have a minimum number of resemblances that need to
Speaker 1: be there in order for you to call it a match. Now,
Speaker 1: usually law enforcement agencies rely on experts who give their
Speaker 1: expert opinion and therefore putting their own reputation on the
Speaker 1: line as to whether or not something matches. And of
Speaker 1: course now these days we rely very heavily on digital information,
Speaker 1: which with very very complex and intelligent i'll rhythms, that
Speaker 1: will that will do some really interesting like work. Yeah,
Speaker 1: and so with that, you know, the the level of
Speaker 1: a confidence grows quite a bit. So, uh, just so
Speaker 1: you know that twelve points of similarity not necessarily a
Speaker 1: legal standard. Nineteen four, that's when Congress enabled had an
Speaker 1: act that established the new division for the Federal Bureau
Speaker 1: of Investigation also known as the f b I. UH
Speaker 1: and this division was called the Identification Division. I bet
Speaker 1: you can guess what it did. So it became kind
Speaker 1: of a centralized fingerprint file for the entire country. So
Speaker 1: not it wasn't necessarily uh standard procedure for every law
Speaker 1: enforcement agency out there to send a copy to the FBI.
Speaker 1: But that's kind of what started to happen, so that, uh,
Speaker 1: there could be this sort of cooperation between different departments
Speaker 1: which often wouldn't have any communication with each other. Sure sure,
Speaker 1: by ninety six, the FBI would have processed more than
Speaker 1: a hundred million fingerprint cards. Yeah, not just processed, but
Speaker 1: they did that by hand, right, right, and it would
Speaker 1: be two million by two million physical cards with fingerprints
Speaker 1: on them. I mean, just imagine how many, Like how
Speaker 1: how much storage you need just for me? It's two
Speaker 1: I can't even I can't even imagine it. But by
Speaker 1: the FBI introduced the Integrated Automated Fingerprint Identification System or
Speaker 1: if SO. It's the largest fingerprint database in the world,
Speaker 1: and its computer automated. It takes about twenty seven minutes
Speaker 1: for the system to comb through every single file in
Speaker 1: its database to find out if there is a potential match.
Speaker 1: During a criminal investigation, it's different. If it's a civil case,
Speaker 1: it's actually like more than an hour. But for criminal investigation,
Speaker 1: for all the criminal files that are storing this database,
Speaker 1: twenty seven minutes from the time you actually input the
Speaker 1: suspects fingerprint. I imagine that's a lot faster than whatever
Speaker 1: in her and they sent down to the basement, Well yeah,
Speaker 1: because I mean you would have to narrow down the
Speaker 1: person quite a bit before you could ever start coming right,
Speaker 1: this is a man, So cut out all the women
Speaker 1: and then go like there are seventy million of them
Speaker 1: down there. Uh yeah, that would be that would be
Speaker 1: a daunting task. So in the digital age, we can
Speaker 1: actually analyze this stuff way better than we ever could,
Speaker 1: Like you don't have to use the naked eye anymore
Speaker 1: and try and find those little ridges and stuff. You
Speaker 1: can actually rely very heavily upon computer systems. And once
Speaker 1: we started getting those computer systems in place, they pretty
Speaker 1: soon thereafter became um commercially available. Yeah. Yeah, we had
Speaker 1: some fingerprint verification systems that have been around for a
Speaker 1: few decades now. On the consumer level, they've only been
Speaker 1: available fairly recently. And you might be thinking, oh, yeah, yeah,
Speaker 1: the iPhone five s because it has that that fingerprint
Speaker 1: scanner where you can use that to log into your phone.
Speaker 1: That's the first smart ohne to ever use that, right, Nope, no, no,
Speaker 1: there's actually a mobile device. The first mobile device that
Speaker 1: I found was a one that dated from two thousand three,
Speaker 1: the H and Boy. The name of this is phenomenal.
Speaker 1: HP names their products in such catchy ways. It's the
Speaker 1: HP I pack, I p a Q P PC pocket PC.
Speaker 1: Oh yeah, it just rolls off the tongue. Yeah, it
Speaker 1: really is. I mean, with a name like that, how
Speaker 1: could you resist I phone my phone. So at any rate,
Speaker 1: this was the first mobile device to incorporate finger scanning technology.
Speaker 1: But it was also sort of the edge of a
Speaker 1: boom for the technology. UM it was being extended for
Speaker 1: for wide consumer use at the time. I mean, you know,
Speaker 1: keyboards and mice had UM, laptops had him. You can
Speaker 1: buy a USB scanner for multipurpose use and encrypt everything
Speaker 1: with your fingerprint, right, you could end up creating, for example,
Speaker 1: with a copier, you could end up telling people, all right,
Speaker 1: this group of folks are authorized to make copy. Anyone
Speaker 1: who's not on this list cannot make copies. And you
Speaker 1: would walk up to make copies. And if you weren't
Speaker 1: on that list, then I guess no fun Christmas party
Speaker 1: Shenanigans for you. But but but but also opening this up
Speaker 1: to the consumer market meant that a lot of people
Speaker 1: started finding the flaws in the technology. Oh yes. In
Speaker 1: December five, clarks And University researchers announced that they could
Speaker 1: fool of the world's fingerprint scanners using an incredibly sophisticated,
Speaker 1: expensive substance. Yeah, they could just go out to toy
Speaker 1: store and buy some Plato and essentially make a copy
Speaker 1: of a fingerprint and put it on any optical scanner,
Speaker 1: and we'll talk about the optical scanners in a little bit.
Speaker 1: And it worked really well. So that gave people some
Speaker 1: pause and thought, maybe we should come up with something
Speaker 1: besides optical scanners too, because fingerprint identification is a great idea.
Speaker 1: But if it's if it's that easy to fool, we
Speaker 1: have to find a different way of measuring it. So
Speaker 1: then there was a totally different expose on September twenty one,
Speaker 1: two thousand and six, when our beloved MythBusters decided to
Speaker 1: do a fingerprint scanner scam of their own. They decided
Speaker 1: to see if they could fool one. And this one
Speaker 1: was a little different. It wasn't just an optical scanner.
Speaker 1: It was supposed to also detect sweat from pores in
Speaker 1: the fingertips. Okay, so so you can't just use a
Speaker 1: lump of plato or photograph. You have to have something
Speaker 1: that sweats has to have to otherwise it's never gonna work.
Speaker 1: So what did they do. They made a latext copy
Speaker 1: of a fingerprint and then they did a very sophisticated
Speaker 1: thing in order to simulate sweat. Yeah, and it worked.
Speaker 1: So if you can't play dough it, lick it, I
Speaker 1: guess is the moral of that story. I think I
Speaker 1: think that that's really what we all should learn from
Speaker 1: this today. Probably, So anyway, they're still seeing this kind
Speaker 1: of technology being rolled out, but it's not just an
Speaker 1: optical scanners, and even optical skins have gotten a lot
Speaker 1: better than they were back in two thousand and five.
Speaker 1: So we're gonna we're gonna cover exactly how they work.
Speaker 1: But before we do that, let's take a quick break
Speaker 1: to thank our sponsor. Alright, I had just talked about
Speaker 1: optical scanners, and those are one of the ones that
Speaker 1: are the easiest to explain and uh and fairly common
Speaker 1: even today. In fact, not my work computer, but my
Speaker 1: home computer has in my home laptop has a little
Speaker 1: optical scanner. So if I want to log in, I
Speaker 1: can just swipe my finger across it. So optical scanners
Speaker 1: use something that is found in digital cameras and camcorders
Speaker 1: called a charge coupled device or c c D. Now,
Speaker 1: essentially that's a light sensor. It's got an array of
Speaker 1: things called photo sites. Now that's light sensitive diodes, and
Speaker 1: it's works pretty much the way you would imagine. So photons,
Speaker 1: those little particles of light when they make a collision
Speaker 1: with these photo sites, it generates a little electrical signal
Speaker 1: and those can then be compiled and converted into a
Speaker 1: digital image. And it's essentially the same process that digital
Speaker 1: cameras used to take pictures. And here's the thing though,
Speaker 1: So if I put my finger on an optical scanner,
Speaker 1: I'm actually blocking light. And unless you happen to be
Speaker 1: et the extraterrestrial, your finger probably isn't emitting light. So
Speaker 1: how the heck is it getting this picture? Well, it
Speaker 1: uses a flash, yeah, except in this case of flash
Speaker 1: is probably like a single LED or for some scanners
Speaker 1: maybe an array of LEDs light emitting diodes in other words,
Speaker 1: and so that provides the light that is necessary to
Speaker 1: take this image. And uh, then the c c D
Speaker 1: creates an image of your fingertip. However, it's a little funky.
Speaker 1: It's inverted, right. The dark areas are going to represent
Speaker 1: the ridges that the raised portions of your fingertip, and
Speaker 1: the light areas are going to represent the values. Yeah,
Speaker 1: so it's kind of like looking at a negative, a
Speaker 1: photo negative. Uh. And it makes sense because stuff that's
Speaker 1: reflecting more light is going to create a lot a
Speaker 1: bigger electra called signal bus creating that. You know, the
Speaker 1: charge couple device is going to make that into a
Speaker 1: darker portion the valleys. The light is not as much
Speaker 1: of it's going to reflect back, so you get a
Speaker 1: weaker electrical signal. That's why it gets lighter. Uh So,
Speaker 1: if you were to scan your finger and UM and
Speaker 1: it tells you that it's a good scan, because most
Speaker 1: of these devices also have some sort of fail safe
Speaker 1: in them that will alert you if there wasn't enough
Speaker 1: enough differentiation between the dark and light parts, right, that
Speaker 1: the same way that you're that your camera UM sometimes
Speaker 1: will take a picture that's that's overdeveloped or underdeveloped, the
Speaker 1: same thing can happen here. Yeah, So if you wanted to,
Speaker 1: like if you most of the software has let error
Speaker 1: function built into it, so it can tell and it
Speaker 1: will ask you to scan again, right, So then you
Speaker 1: would scan again. So if it's the first time you're
Speaker 1: using it, then you would also end up creating a
Speaker 1: profile in some way. It might not be you, it
Speaker 1: might be an administrator, but something that links the fingerprint
Speaker 1: to who you are and what says you are supposed
Speaker 1: to have will happen then on subsequent uses, what will
Speaker 1: happen is that when you scan your finger it will
Speaker 1: go through its database of of identities that have fingerprints
Speaker 1: attached to them look for you. If you're there, then
Speaker 1: it will authorize you for whatever use you're allowed. So,
Speaker 1: for instance, on my home computer, I've given myself very
Speaker 1: strict restrictions because I am not to be trusted. Uh,
Speaker 1: And so all I'm able to do is play a
Speaker 1: pirated copy of Flappy Bird. That's not true, I don't
Speaker 1: have Flappy Bird. But at any rate, you know that's
Speaker 1: the basic You know, that's the basic procedure, right, and
Speaker 1: and so if your finger print is not found in
Speaker 1: that database, you get an error. So either you have
Speaker 1: to swipe it again or or scan it again if
Speaker 1: it's not swipe all depends on what kind of scanner
Speaker 1: you're at, or you end up saying the jig is up,
Speaker 1: you got me, I don't really belong here, and then
Speaker 1: you run away. Um. So that that's the basic thing,
Speaker 1: and what they're looking for. It's not the entire pattern
Speaker 1: of your fingertip. It's looking for for a specific minutia
Speaker 1: about it. Uh. Certain types of patterns and it and
Speaker 1: it depends on the software that the scanner is using.
Speaker 1: Um it might be the places where the ridges converge
Speaker 1: um or or split apart at the end, or um
Speaker 1: any any other kind of detail. It's going to be
Speaker 1: unique to you. Right. So in other words, all has
Speaker 1: to do is say, hey, there are these three points
Speaker 1: on this fingertip, uh that are unique that that's all
Speaker 1: I'm concerned about. And if the fingerprint that scan has
Speaker 1: those three points, I know it's this person and they
Speaker 1: can be let through by constraining on the minutia, then
Speaker 1: you really cut down on all the rest of the
Speaker 1: data that's necessary to have a verification. Right, you can
Speaker 1: kind of throw everything else out and concentrate on that
Speaker 1: and right. Uh And and they're pretty good, like we said,
Speaker 1: though they can sometimes be fooled by a really high
Speaker 1: quality picture of a fingerprint. Right. So what if you
Speaker 1: instead of looking at a picture, you were to measure
Speaker 1: the fingerprint in some other way, such as capacitance right,
Speaker 1: because capacitense touch screens are totally a thing. Yeah, so
Speaker 1: it's very similar to what a regular capacityans touch screen is.
Speaker 1: So you know, there are different ways of doing touch
Speaker 1: screens as well. There's somewhere you have to use pressure.
Speaker 1: With the benefit of that is you could be wearing
Speaker 1: gloves and still work a pressure version. The downside is
Speaker 1: that when people are expected to apply pressure to delicate material,
Speaker 1: they sometimes destroy it completely, right, or it'll at least
Speaker 1: decrease the lifespan of that object by quite a bit. Capacitance, however,
Speaker 1: uses weak electric fields, So when you make contact with
Speaker 1: a screen, a touch screen, that's using capacitance. Uh see,
Speaker 1: you're a conductor. I don't mean that you conduct trains,
Speaker 1: Nor do I mean that you Maybe you do. Maybe
Speaker 1: you do, Maybe you do. Maybe you conduct orchestras. Maybe
Speaker 1: you conduct orchestras on a train. I don't know, but
Speaker 1: I know what I'm talking about. If you do, call us,
Speaker 1: because that sounds fascint, would be kind of cool. Actually,
Speaker 1: But now I'm talking about electrical conductivity. So we can
Speaker 1: conduct electricity. It's not great for us to have a
Speaker 1: lot of it, but tiny amounts don't hurt us. Sure,
Speaker 1: And as it turns out, the ridges and valleys on
Speaker 1: your fingers conducts slightly different amounts of electricity. This blows
Speaker 1: my mind. I mean to think that the raised parts
Speaker 1: of your fingerprint, and the valleys of your fingerprint are
Speaker 1: distinct enough to create a measurable difference in capacitance. You know,
Speaker 1: It's something I never would have imagined. And it's really
Speaker 1: a sensor issue here. I mean the fact that we
Speaker 1: can create these these cells, these capacitor plate cells that
Speaker 1: are sensitive enough to tell that yeah technology. So what's
Speaker 1: happening is when you put your finger down on one
Speaker 1: of these capacity scanners, you are actually you're acting as
Speaker 1: a capacitance plate, right, your fingertip is acting is one,
Speaker 1: and you already have other ones inside the scanner itself,
Speaker 1: and it will end up creating voltages and there will
Speaker 1: be difference differences in those voltages. The differences between the
Speaker 1: ridges and the valleys based on how far away they
Speaker 1: are from the from the cells. Yeah, so if it's
Speaker 1: a valley, it's going to be lower capacitance because the
Speaker 1: distance is greater. Capacitance is very dependent upon distance. So
Speaker 1: if you move to capacitance plates far enough apart, they
Speaker 1: will not be they will not work together. So it's
Speaker 1: amazing that the valleys, just by being that much further
Speaker 1: away will create a different voltage than the ridges. And
Speaker 1: then having a whole whole set of these cells set
Speaker 1: up next to one another. UM it allows the scanner
Speaker 1: to to sort of make a digital picture of your fingerprint,
Speaker 1: but just using electricity rather than light. The data from
Speaker 1: each one is again compiled and then converted into an
Speaker 1: image of sorts. Yeah. Yeah, you can think of it
Speaker 1: as like an image made with electricity. And this is
Speaker 1: the sort of scanner that the iPhone five S uses,
Speaker 1: so it's not an optical scanner. One of the big
Speaker 1: benefits of this technolog g is that it's easier to
Speaker 1: make it really compact and manaturized, which is why you
Speaker 1: could find it in things like handheld electronics, right sure. Um. However,
Speaker 1: this technology can also be fooled UM sometimes by by
Speaker 1: mold of a finger UM or if someone has gone
Speaker 1: and calibrated the scanner to look for things like like
Speaker 1: heat or a pulse. UM. You can you can use
Speaker 1: one of those movie tricks, like a gelatine or silicone
Speaker 1: mold of a finger UM pasted onto a different different finger. Yeah.
Speaker 1: My favorite version of getting past a UM capacitance or
Speaker 1: an optical scanner is to use the finger that's been
Speaker 1: removed from the person who had the authorization. Yeah, yeah, sniping,
Speaker 1: that's that's that's your favorite. That's my favorite out in
Speaker 1: the field. That's what you like. We had this discussion
Speaker 1: about the born identity before we came into the podcast.
Speaker 1: This is totally true. Uh, I don't like to discuss
Speaker 1: my actual field operative kind of mentality and strategies, but yes,
Speaker 1: I do love doing that. So thermal scanners, well, this
Speaker 1: one's a little different because it's a it's a heat scanner,
Speaker 1: and again it's one of those ideas where it measures
Speaker 1: the differences in heat between ridges and valleys. Once again,
Speaker 1: you're going to get a slightly higher temperature from the
Speaker 1: ridges than you do with the valleys. The valleys that
Speaker 1: are essentially pockets of air. There's some downside with this one.
Speaker 1: One of the problems with thermal scanners is that if
Speaker 1: you if it takes too long to do the scan,
Speaker 1: the temperature differences are going to equalize across the and
Speaker 1: wind up you just get a blank fingerprint, like a
Speaker 1: big blank fingerprint. Not useful. This next one is super cool.
Speaker 1: It's ultrasonic ultrasonic sensors, so right, Yeah, we did a
Speaker 1: whole episode about ultrasound called How Ultrasound Works. Crazily enough
Speaker 1: that published on January if you would like to hear
Speaker 1: all about how this technology works. But um, but it's
Speaker 1: essentially echolocation. Yeah, you're sending out sound signals and then
Speaker 1: you're waiting for them to bounce back, and by measuring
Speaker 1: the amount of time it took to go out and
Speaker 1: come back, you get an idea of how far away
Speaker 1: something is. Well, that works, you know, in lots of
Speaker 1: different ways, including being able to tell a fingerprint, being
Speaker 1: able to read a fingerprint. It can go even deeper
Speaker 1: than that, exactly, it can go into tissues. So if
Speaker 1: you wanted, you could create an ultrasonic fingerprint scanner that
Speaker 1: scan not just the fingerprint itself, but the underlying veins
Speaker 1: that are in your finger which also are going to
Speaker 1: be unique to you. So that's a lot harder to
Speaker 1: fake than a fingerprint. Like you're not going to get
Speaker 1: a really high resolution image of veins and then create
Speaker 1: a fake finger easily. It would be really difficult. I mean,
Speaker 1: but you could use, um your favorite application, which is
Speaker 1: removing someone's finger and that right unless you had also
Speaker 1: built into the software to detect living tissue, because to
Speaker 1: see if blood is moving through the veins the vessel.
Speaker 1: If it's not detecting blood, it's good to say, y'all,
Speaker 1: this is messed up. You need to send someone down
Speaker 1: right now. The fingerprint scanner. Things that are bad are happening.
Speaker 1: That's exactly what the voice it uses too. I I
Speaker 1: assumed I run into it in the field all the time.
Speaker 1: So yeah, I mean this is uh, you know, that's
Speaker 1: we're making light of it because to be serious about
Speaker 1: it is so squeaky. But at any rate, it does
Speaker 1: mean that you can build those sort of parameters in
Speaker 1: so it's not just looking at the fingerprint and the
Speaker 1: veins underneath, but also to make sure it is truly
Speaker 1: a valid uh entry, so that they don't you know,
Speaker 1: you don't end up compromising security. Um and there there's
Speaker 1: also I wanted to mention very briefly the difference between
Speaker 1: those static uh fingerprint scanners, especially the optical ones where
Speaker 1: you just hold your finger down and you wait for it.
Speaker 1: It's kind of like a copier, right right, and the
Speaker 1: swipe style that you were talking about having on your
Speaker 1: home laptop exactly. So if you've ever had a laptop
Speaker 1: or any other device that has like a narrow window
Speaker 1: and you're supposed to swipe your finger across that window.
Speaker 1: The reason for that is that it's actually taking in
Speaker 1: a series of quote unquote images of your finger. However,
Speaker 1: the implementation is actually being used. It's it's doing then
Speaker 1: a quick series. Machines are really fast, so they can
Speaker 1: do this without any real problem. They're looking for those
Speaker 1: minutia that we talked about before, and they're able to,
Speaker 1: uh to use software to compile them. But you know,
Speaker 1: it's it's it's nifty having the smaller form factor because
Speaker 1: like we said, uh, then you can miniaturize, you can
Speaker 1: put them in something like a cell phone and also
Speaker 1: make them cheaper. Exactly. Yeah, you've got this little window
Speaker 1: and your finger moves past the window instead of the
Speaker 1: window having to be big enough to So it's it's
Speaker 1: really uh an interesting development and uh pretty cool. Also,
Speaker 1: we can mention that biometric systems, many of them, not
Speaker 1: necessarily all of them, but many of them end up
Speaker 1: translating your fingerprint into an algorithm that or an algorithm
Speaker 1: rather does the translating that turns it into a bunch
Speaker 1: of ones and zeros, all right, right. A digitization um
Speaker 1: sometimes called a hash. It's like a personal code like
Speaker 1: a really long pen. Yeah. So in this case, what
Speaker 1: you would say is that it's not storing an image
Speaker 1: of your fingerprint. It's not like if you were to
Speaker 1: somehow hack into the computer you would suddenly see a
Speaker 1: on your screen representation of your fingerprint. It would just
Speaker 1: mean that it would take the the pattern of ridges
Speaker 1: and valleys and all the night nutia convert that into
Speaker 1: this this hash, this this long string of ones and zeros,
Speaker 1: and the next time you scan it, if the if
Speaker 1: the same hash comes up, then it as a match
Speaker 1: and it says, all right, identification has been verified. But
Speaker 1: it's not actually like an actual, real image of your fingerprint.
Speaker 1: And the reason why a lot of these companies try
Speaker 1: to talk about you know this as as a big
Speaker 1: selling point is that it doesn't allow you to recreate
Speaker 1: a person's fingerprint if you were to get hold of
Speaker 1: those hashes. So it's not like you would say, oh,
Speaker 1: if I just put this through an image program, I
Speaker 1: suddenly get a picture of that fingerprint. You would just yeah,
Speaker 1: that's that's the way I think that the iPhone five
Speaker 1: S and the Galaxy something something that the latest Samsung
Speaker 1: incorporates it, and um PayPal, these Days even has um
Speaker 1: fingerprint signatures on their app, and any any device that
Speaker 1: allows you to in to scan in your fingerprint will
Speaker 1: let you pay for stuff on PayPal with that signature.
Speaker 1: I'm sure we're going to see a lot of that
Speaker 1: kind of stuff incorporate with things like the NFC technology
Speaker 1: or even the low Bluetooth energy low energy Bluetooth. Rather,
Speaker 1: I should say, uh, implementations where your fingerprint instead of
Speaker 1: having to put in a pen, you just swipe your
Speaker 1: finger Yeah, you know, I don't know. I kind of
Speaker 1: hope that it's an additional safety feature, not a standalone
Speaker 1: safety feature, because you know, unlike a password or a pin,
Speaker 1: you can't just change your fingerprint if it gets stolen,
Speaker 1: and this hash issue adds security to to the whole thing.
Speaker 1: It's harder to but I'm sure that someone if they
Speaker 1: really wanted to, could decode a hash and figure out
Speaker 1: what that scan looks like. Yuh maybe, I mean, they
Speaker 1: would have to have a lot of information, but it
Speaker 1: is It is important to say that there is no
Speaker 1: security feature out there that's going to be perfect, right right,
Speaker 1: There's nothing out there, so having it as an additional tool,
Speaker 1: I agree, Lauren, that's that's the best way of looking
Speaker 1: at it. I think anytime we decide that we're going
Speaker 1: to rely on a specific implementation and that's it and
Speaker 1: we're done, we're good, then we're pretty much dooming ourselves
Speaker 1: to getting hacked in some way down the line because
Speaker 1: people are smart and they figure out ways around rules
Speaker 1: they do, and I really don't want to have to
Speaker 1: change my fingerprints, not again. All right, So that wraps
Speaker 1: up this episode of tex Stuff. Folks, if you have
Speaker 1: suggestions for future topics, you should let us know because
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