"Email-Firewalls" / Instant Corporate PGP

[Vincent.Cate@FURMINT.NECTAR.CS.CMU.EDU]

Companies like the idea of firewall machines to protect the security of
their internal nets.  I bet they would also like something called an
"email-firewall".  Names are important. :-)  I think of the
email-firewall as a slightly modified anonymous-remailer.

Outsiders could send encrypted mail to the remailer and it would
decrypt it and send it on to the right person inside the company over
internal (more secure) nets.

The email-firewall could also encrypt outgoing mail when it was going
to a person who either had a listed PGP key or who was working at
another company with an email-firewall.

Also, this remailer would not make the mail anonymous.  Corporations
need security, not anonimity.

Each company would only need to buy one copy of ViaCrypt PGP.  For a
company this cost is, of course, negligible.

With this people inside the company would not need to deal with the
encryption directly.  They getting encrypted mail would not take
anything new, and sending might take a slight change.

Of course this is only a step towards true end-to-end encryption, but
it is easy and far better than what they have now.  Also, it fits with
the way companies work.  There is a security guard at the entrance to
the plant, but once inside people generally trust each other and don't
worry about security.  With this, internal mail is still like
postcards, but external would have an envelope.  

I thought about this after making a short script (below) so that mail
to vac+pgp@cs.cmu.edu (the low security envelope) would be decrypted
automatically.  This also needed the following line in my .maildelivery:

Addr vac+pgp          pipe ? /usr/vac/pgp/incoming

I am not going to make the "email-firewall" at this time, but thought I
would throw the idea out.  Has anyone done this?   Let me know if you
do.

One question.  How do I extract 2 public keys into one ASCII 
keyblock?  Now that I want to make 2 keys FTPable ...

  -- Vince


#!/bin/csh -f
#
#  Vince Cate

setenv PGPPATH /usr/vac/pgp
setenv PGPPASS "not really vinces passphrase"

cd $PGPPATH

cat > mailtmp.asc

egrep 'Date:|From:|Subject:|To:' mailtmp.asc >  mailtmp
echo " "                                     >> mailtmp

pgp -f < mailtmp.asc                         >> mailtmp

/usr/ucb/mail -s "Was encrypted" vac < mailtmp

exit 0