From: "Paul S. Penrod" <furballs@netcom.com>
Date: Thu, 16 May 1996 15:36:40 +0800
To: cypherpunks@toad.com
Subject: Re: Fingerprinting annoyance
In-Reply-To: <Pine.SUN.3.93.960514093526.3611C-100000@polaris.mindport.net>
Message-ID: <Pine.3.89.9605151204.A27377-0100000@netcom6>
MIME-Version: 1.0
Content-Type: text/plain




On Tue, 14 May 1996, Black Unicorn wrote:

> On Mon, 13 May 1996, Paul S. Penrod wrote:
> 
> > 
> > 
> > On Mon, 13 May 1996, Mark O. Aldrich wrote:
> > 
> > > On Mon, 13 May 1996, Senator Exon wrote:
> > > 
> > > <snip>
> > > > i can fill out and manipulate the card myself i just need a
> > > > working method.
> > > > is there no privacy advocate who can help me?
> 
> [...]
> 
> > > If you're forced to do this in person with a tech, you can continuously 
> > > "fight" the grip they have on your hand and smudge the card.  However, 
> > > they'll not submit the card until the prints are "good," so this sort of 
> > > betrays your intent of at least appearing to cooperate with them.  In the 
> > > law enforcement community, they are taught how to take prints by force 
> > > but it's unlikely that your tech will attempt any such technique.
> > > 
> > 
> > I know of no such instance (other than some informal "fingerprint the 
> > kiddies for safety" schtick) where it's a do-it--yourself operation. 
> 
> Not _technically_ perhaps.  But in most cases it's a
> go-down-to-the-police-station-and-have-them-sign-the-card operation.  Who
> is it that can tell a random signature from a police signature exactly?
> Like I said, standard print cards are available at the GPO.

Thats fine, but tell me it's going to play at the clearance level...It 
won't.

> 
> > While the methods listed are clever, they and many other finaglings are 
> > the main reason it's done in the "light of day" by a tech.
> 
> Or _theoretically_ done in the light of day by a tech.
> 
> > > You can mutilate the tips of your fingers so that prints cannot be 
> > > acquired, but this hurts.  Badly.
> > 
> > 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.

> 
> > > 
> > > You could get some false latex coverings for your finger tips, but they'd 
> > > have to be damn good to fool a tech.  Likely to cost big bucks, too.
> > 
> > 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.

> 
> > > 
> > > I know of no chemical or physical "pre-treatment" that can be used to 
> > > hack the ink transference process.  Perhaps one of the chemists here on 
> > > the list might know of some good technique.
> > 
> > Pineapple juice and other weak acidic subtances ruin the ridges on the 
> > finger tips causing them to smear or not show at all. Unfortunately, this 
> > takes a period of time and constant handling of such items.
> 
> This is interesting.  I suspect that you'd have to have major damage to
> the ridges however.
> 

There needs to be suffcient damage to the ridges by some chemical or 
mechanical means (sand paper, concrete, brick, etc.) to remove the 
distiguishing ridges, and not replace them with a traceable pattern of 
any kind. 

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.

...Paul