Yet Another Fingerprint Fantasy

October 14th, 2014

They talk about art imitating life, but more often than not, there’s only a slight resemblance of the former to the latter. Take a recent episode of a police detective procedural, the rebooted “Hawaii 5-0,” which had a plot device that might present concerns about the Touch ID fingerprint sensor on an iPhone. Before I go on, though, remember that TV dramas are obviously just fiction, even if they are loosely based on facts or ripped from the headlines. Besides, this particular show has no such pretense, but the public might still get the wrong idea.

Here’s how the story played out. It seems that three bikini-clad women staged a robbery on a touring bus, stealing, among other goods, a smartphone from a man who is shot and killed during that scene. Shortly thereafter, someone pretending to be the guy’s wife visits the medical examiner’s office and manages to grab his thumbprint. The staff doctor isn’t smart enough to realize something is amiss. But it’s strongly implied that the thumbprint will be used to gain access to smartphone.

This is the episode’s fatal flaw, or at least one of them.

You see, you can’t just make a scan of someone’s fingerprint and use it to grant access via Touch ID, let alone other fingerprint recognition systems. These systems generally require the presence of a living thumb or other finger. By the same token, the grisly image of cutting off someone’s thumb to accomplish the deed is equally false. Remember that the removed digit is not alive. But logic and facts don’t matter on a TV show; it’s about grabbing an audience and hoping you’ll pay attention to one of the commercials.

In the world of TV, a crime has to be solved in 43 minutes or, if there’s a cliffhanger continuing the story in another episode, it’s 86 minutes. But I wonder how the pitch meeting went for that episode, and whether they had a consultant on board to look at how smartphone fingerprint sensors really worked, and if there were legitimate ways to beat the system within the constraints of a TV show. But perhaps I’m asking too much.

But when it comes to fear mongering about the value of a fingerprint sensor, this harkens back to 2013, days after Apple released the iPhone 5s with Touch ID. Someone made a cast of a fingerprint and allegedly planned to use it to break into one of these iPhones. That won’t work either. Some might suggest using some sort of plastic surgery to transfer someone’s fingerprints, but I don’t have the medical knowledge to assume it’s possible or even practical. It would be easier to just kidnap the victim and force him or her to comply.

In the real world, Touch ID, when it works, can’t be defeated directly. But you can still work around the need for a fingerprint by guessing one’s passcode. Either works, and you must fall back to the passcode when you restart your iPhone with Touch ID.

In the early days, Apple’s fingerprint sensor didn’t always work so well. In some cases, recognition accuracy would diminish over time. I suppose if you had an injury that made your fingerprints less visible, that might also eliminate the feature’s usefulness. But ongoing improvements in iOS 7 and in iOS 8 have made it pretty reliable otherwise. Since iOS 8 came out, it hasn’t missed a beat for me.

Contrast that to the fingerprint sensor on the Samsung Galaxy S5, which isn’t mentioned very much nowadays. Instead of just placing your finger on the sensor, you have to slide it in a weird fashion that is difficult to repeat reliably. Some reviewers remarked that the feature barely worked. Even Consumer Reports, which tends to give Samsung gear a pass, remarked on the two tentpole features of the S5, “…some of the new features, including the fingerprint scanner and heart-rate monitor, are a little rough around the edges. I found it often took multiple attempts to get either to do its promised job.”

Little rough? Talk about understatement. How about barely useable, particularly the fingerprint scanner? Now if Touch ID were that bad out of the starting gate, you’d bet that Apple would be working full-time for a solution, and would be issuing one of those rare public apologies. Consider how Tim Cook responded to the original release of the seriously flawed Maps for iOS 6, and how he even recommended competing map apps until things were sorted out.

Today, we don’t hear much about Maps, except when some tech pundits remember the original problems and imagine they were never fixed. But those are often the same writers who strangely overlooked the beta warnings on Google Maps, and seldom draw attention to that service’s failures. These navigation apps are definitely not perfect by any means. But I still wonder why there still hasn’t been a thorough two-years-on comparison, at least that I know of, between Google and Apple. Let’s see how they fare now.

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5 Responses to “Yet Another Fingerprint Fantasy”

  1. Sponge says:

    In regards to TV shows and their commitment (or lack thereof) to reality, I have a friend who is a former FBI agent who has been a paid consultant for a number of TV shows and movies. In his experience, the producers don’t care about authenticity if it gets in the way of a plot device, or especially a good explosion (if cars blew up or burst into flames in real life as often as they do on film, they’d be illegal). The problem is that even rational people often end up believing what they see on TV without even realizing it—seeing is often believing even if it’s in a show or movie. I was in a minor fender bender some years ago, and as we got out of the car one of the other passengers immediately started running full speed away from the car, despite there being no smoke or other indicators of danger. They thought the car was going to blow up or be engulfed in flames—after all, that’s what happens on TV, right?

  2. melgross says:

    As much as I hate to say this, if you do get a good print, you can make a latex or silicone finger with it, and it will work if you breathe on it to moisten it. We’ve seen this work twice, so it isn’t just fiction.

    The problem is retrieving a useable print, which is very difficult. A dead finger would work very well for that purpose, but not a phone screen, particularly if it has an oleophobic surface as Apple’s products do.

  3. dfs says:

    And, of course, if you REALLY want to access somebody’s Apple mobile, you can always chop off one of his fingers.

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