Fingerprints (was: Re: biometrics)

[Derek Atkins]

JI,

Keep in mind that this is the _creation_ of the database entry.  Yes,
you want the data in the database to be as completely accurate as
possible.  Later, when they only have partial prints, they can perform
a lookups of partial data using the complete database.  I think the
same would be true of mass-produced fingerprint scanners.

So long as the backend-database has a full, complete data set,
a partial read on the verification step can still match.

The question is: what would be the rate of false-positive (or
false-negative) readings?

-derek

ji at research.att.com writes:

> Last week I had to go to my local INS office to get fingerprinted
> (part of the green card process is getting your fingerprints OK'ed by
> the FBI (and also presumably stored for future reference)).  The
> process is computerised, with a low-res scan of all the fingers taken
> once, and then each finger is individually rolled and scanned on a
> much higher resolution scanner.  
> 
> The process took about 20-30 minutes;  each finger had to be wiped
> with some cleaning fluid, the glass on top of the scanner also had to
> be wiped between scans, and a fingerprinting technician had to roll
> each of my fingers with the right amount of pressure to get a clear
> image of the fingerprint.  Even with immediate feedback on a large
> screen showing the fingerprint and how good the scan was, some fingers
> took as many as five tries to get an acceptable fingerprint.
> 
> Now, this was a special-built device whose only purpose is to scan
> fingerprints, operated under ideal conditions by a trained
> technician.  Draw your own conclusions about the effectiveness of
> mass-produced fingerprint scanners that would be integrated in other
> devices.
> 
> /ji
> 
> --
>  /\  ASCII ribbon  |  John "JI" Ioannidis * Secure Systems Research Department
>  \/    campaign    |  AT&T Labs - Research * Florham Park, NJ 07932 * USA
>  /\    against     |  "Intellectuals trying to out-intellectual
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> 
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-- 
       Derek Atkins, Internet and Computer Security Consultant
       IHTFP Consulting (www.ihtfp.com)
       derek at ihtfp.com



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