From: Steve Reid <steve@edmweb.com>
Date: Mon, 29 Apr 1996 22:34:42 +0800
To: Rich Graves <llurch@networking.stanford.edu>
Subject: Re: PGP and pseudonyms
In-Reply-To: <Pine.GUL.3.93.960428201204.13032R-100000@Networking.Stanford.EDU>
Message-ID: <Pine.BSF.3.91.960429000141.11364B-100000@kirk.edmweb.com>
MIME-Version: 1.0
Content-Type: text/plain


> > I suppose a temporary fix would be to not use an ordinary PGP passphrase,
> > but rather encrypt the whole secring.pgp file. Decrypt it when you need
> > it, and be very careful to properly clean up when you're done.
> Huh?
> Just use multiple secring.pgp files, and toggle PGPPATH. What's the
> problem? 

You don't understand the problem we're concerned about... The problem is,
the "real" person is in posession of the pseudonym's secret PGP key, and 
PGP doesn't try to hide that fact.

Suppose John Doe is using the pseudonym "Evil Bastard". Naturally, he has
a PGP key for his Evil Bastard identity. Now suppose someone gets into his
computer. This person would be able to find Evil Bastard's secret key. 
Fortunately, the snoop would not be able to use the key, since it would be
encrypted with a secure PGP passphrase. However, they would still be able
to use the command "pgp -kvv secring.pgp", and that shows the key ID of
each secret key. 

The key ID is the lower 64 bits of the public key, but it's included in
unencrypted form on the secret keyring as well, to identify the secret
key. The person who snooped the secret keyring would be able to see that
John Doe has the secret key with the ID of (for example) 13579BDF. Since
the ID of Evil Bastard's well-known public key is also 13579BDF, the snoop
now knows that John Doe is in posession of a secret key that corresponds
to Evil Bastard's public key, which proves that John Doe *IS* Evil Bastard. 


=====================================================================
| Steve Reid - SysAdmin & Pres, EDM Web (http://www.edmweb.com/)    |
| Email: steve@edmweb.com   Home Page: http://www.edmweb.com/steve/ |
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|              -- Disclaimer: JMHO, YMMV, IANAL. --                 |
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