dsandler.org/wp

Look Ma, no fingers!

October 2nd, 2007

Wired: New Fingerprint Tech Could Mean Never Losing Your Keys Again. Or, put another way: “New Fingerprint Tech Could Mean Never Being Able To Change Your Locks Again.”

Fingerprint recognition came into wide use in forensic investigations in the early 20th century. Ever since, sci-fi writers and scientists have dreamed of using the unique skin contours on our fingertips to tell our machines we really are who we say we are. The problem is that the number of errors has just been too high.

The article breathlessly continues, extolling the new technology, but judders awkwardly to a halt at the privacy discussion. You can almost hear the sneering tone as they describe the tinfoil-hat Butlerian-jihading naysayers:

No story about biometrics is complete without mentioning privacy concerns. As they say in business, if you can measure it, you can manage it. And not everyone wants to be managed, especially if the government or a big corporation has the calipers.

This is a part of the right argument, but presented in the wrong way. It’s not that “not everyone wants to be managed.” I’m not trying to stay off “the grid” or anything—I use credit cards, I like advertising, I have a blog—but an increase in the use of biometrics for authentication still scares the pants off me.

The real problem is always this: how would you revoke that token if it were compromised? Passwords can be changed; door locks can be re-keyed. What about your fingerprints?

(US residents: Think about how damaging it is to have your Social Security number stolen. This is much, much worse.)

You can leave a response, or trackback from your own site.

One Response to “Look Ma, no fingers!”

  1. jstewart  

    Ironically, New Scientist had an article last week on an attack against online fingerprint schemes:

    magine being free to forget all of your passwords and use your fingerprint to log in to your online bank, eBay and email accounts. This tantalising vision has suffered a major blow: the scheme that makes it possible could also allow hackers to steal fingerprints and impersonate their victims.

    Biometric-secured laptops store an image of your fingerprint, only letting you log in if you produce the matching finger. Proving your identity over the internet is more difficult, however, because the fingerprint data must be transmitted, giving snoopers the chance to hijack it.

    Encrypting the fingerprint using conventional cryptography and then transmitting it is not an option as it would require the fingerprint scanned with your PC to exactly match the one stored by the website you wish to access. That isn’t possible because fluctuations in the way fingers roll over scanners makes the same print slightly different each time.

    Instead, a cryptographic scheme known as the “fuzzy vault” was devised that does not require a print to look exactly the same each time it is scanned.

    …

    Now Preda Mihailescu at the University of Göttingen in Germany has shown that the fuzzy vault is not secure (www.arxiv.org/abs/0708.2974v1). His analysis shows that if more than about 500 chaff pairs are used, too much computing power is required to separate the true pairs from the chaff for the server to cope. Yet he also found that a fuzzy vault with about 500 chaff pairs can be broken in a day using a powerful desktop computer.

    The original paper: http://www.arxiv.org/abs/0708.2974v1

    comment posted at 10:14 am on 03 Oct 2007

Leave a Reply

html help (show)
newer: Banned again. older: Banned from Reddit.