From: "Paul S. Penrod" <furballs@netcom.com>
Date: Sat, 18 May 1996 19:20:29 +0800
To: Black Unicorn <unicorn@schloss.li>
Subject: Re: Fingerprinting annoyance
In-Reply-To: <Pine.SUN.3.93.960515194016.10635M-100000@polaris.mindport.net>
Message-ID: <Pine.3.89.9605152359.A895-0100000@netcom10>
MIME-Version: 1.0
Content-Type: text/plain




On Wed, 15 May 1996, Black Unicorn wrote:

> On Wed, 15 May 1996, Paul S. Penrod wrote:
> > On Tue, 14 May 1996, Black Unicorn wrote:
> > > Paul S. Penrod wrote:
> 

<...>

> > > > Doesn't always work. Partials can be extrapolated to yield a
> > > > relative match.
> > > 
> > > Depends on what you are looking to do.  If your goal is to deter random
> > > searching through a national database, mutilation will probably be very
> > > effective.  If they have the prints of the murderer (you) and you're a
> > > suspect, mutilation aside from actually removing the fingers isn't going
> > > to do anything.
> > 
> > If there is a serious crime involved, partials are sufficient to make the 
> > "guest list" if there are other mitigating factors to even suspect you 
> > might be involved. That's doesn't mean you'll make it to the top, but it 
> > can certainly cause some painful scrutiny.
> 
> Again, it depends on the degree of "mutilation."  Distortion of major
> features is fairly effective even against partial attempts which are
> matched by computer.

Agreed, but there are other factors to consider. For example, it is not 
everyday that someone runs their fingers over sandpaper (via sander or 
not). This may indeed destroy the tell-tale finger print initially, but 
it leaves a distinguishing pattern, that can be matched to other evidence 
such as blood, DNA, fiber, etc. In some instances like this, the computer 
is useless to match finger prints, and balance of the decision rests with 
incriminating evidence. To wit: the "mutilated pattern" provides key 
identification if a good print is lifted and matched directly to the 
suspect - even though a copy of the "new" print doesn't exist.

> 
> [Laytex]

The smart ones use this for starters..

> 
> > > > Wont work. The hands are checked first for signs of tampering.
> > > 
> > > See above about tech end around.
> > 
> > Again, process will work, but not allowed in context of clearance.
> 
> Concur.
> 
> > Scraping the fingertips runs the risk of leaving trace marks that are 
> > just as good as the ridges you tried to remove - even better if you've 
> > left finger prints as a result. The point to the game is not to search 
> > any database, but to produce a verifiable match with evidence at the 
> > scene of any crime. In the case of a clearance, it is to start or 
> > validate an identification process. IF validation is unobtainable via 
> > fingerprints, then the issuing body can employ other means (such as 
> > retinal scans) or deny clearance all together.
> 
> Careful.  Even Central Intelligence Agency print requirements are for
> criminal background check only.  They will run through FBI files and so
> forth and keep the prints for their records, but they are rarely if ever
> used as identification verification per se.
> 
> This is because not everyone in the world has fingerprint files floating
> around.  If you are getting printed for the first time ever and you
> distory or mutilate, there's nothing to compare to.  Further, if you just
> distort, you're prints later might not match well when computer searches a
> nationwide database (which excludes CIA employees in any event).
> 
> It's all about application.

I never maintained that the CIA or other body employs more than the standard 
issue. What I am saying is that there are other methods out there to 
validate means believed to be compromised - should a situation warrant 
such invasive techniques. I have never encountered any situation that 
called for anything other than fingerprints - even inside DoD (which in 
my opinion can be far more paranoid than the agencies).

> 
> To repeat, if you're looking to "estlablish" a false print index,
> distortion is a good way to do it.
> 

Agreed.

> If you're looking to evade a search which has already narrowed you down
> well, hack off some fingers.
> 

whatever...

...Paul