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From: mccoy@ccwf.cc.utexas.edu (Jim McCoy)
Newsgroups: sci.crypt
Subject: Re: Fifth Amendment and Passwords
Message-ID: <1qv83m$5i2@geraldo.cc.utexas.edu>
Date: 19 Apr 93 22:12:06 GMT
References: <1993Apr15.160415.8559@magnus.acs.ohio-state.edu> <C5Jzsz.Jzo@cs.uiuc.edu> <1993Apr18.233112.24107@colnet.cmhnet.org> <1993Apr19.180049.20572@qualcomm.com>
Reply-To: mccoy@ccwf.cc.utexas.edu (Jim McCoy)
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In article <1993Apr19.180049.20572@qualcomm.com>, karn@unix.ka9q.ampr.org (Phil Karn) writes:
> In article <1993Apr18.233112.24107@colnet.cmhnet.org>, res@colnet.cmhnet.org (Rob Stampfli) writes:
> |> >Sadly, it does not. Suspects can be compelled to give handwriting and
> |> >voice exemplars, and to take blood and DNA tests.
> |> 
> |> I am sure that Mike is correct on this point.  I am also pretty sure that
> |> administering "truth serum" would be ruled a violation of your right
> |> not to incriminate yourself.  But, what is the salient difference?
> 
> You can find the salient difference in any number of 5th amendment
> related Supreme Court opinions. The Court limits 5th amendment
> protections to what they call "testimonial" evidence, as opposed to
> physical evidence.

I have a question that is a slight variation on the previously mentioned
examples that perhaps people could give me some pointers on (it has been a
couple of years since my Con Law class in college so I hope I am not
missing something obvious here...)

Basic Scenario:

	I set up a bbs that uses public-key encryption and encryption of
	files on disk.  The general setup is designed so that when users 
	connect they send a private key encrypted using the system public
	key and the user's public-private keypair is used to wrap the
	one-time session keys used for encrypting the files on disk.  The
	result of this is that even if I reveal the system private key it
	is impossible for anyone to gain access to the files stored on the
	machine.  What is possible is for someone to use the revealed
	system private key to entice users into revealing thier personal
	private keys during the authentication sequence.

Questions:

	Does the fact that the system private key does not provide any
	information useful for a search give me any protection as far as
	being coerced to reveal the key?  (I doubt it myself..)

	It seems providing the system private key does not mean that I am
	assisting in "entrapment" (the users would send thier key anyway
	and are not being enticed into doing something they would not
	otherwise do) but is there any other hook that can be used?

	Would the user private-key enticement require wiretap approval?

Any answers or general musings on the subject would be appreciated...

jim
-- 
Jim McCoy                |  UT Unix Sysadmin Tiger Team
mccoy@ccwf.cc.utexas.edu |  #include <disclaimer.h>
j-mccoy@nwu.edu          |  pgp key available via finger or upon request
