From: Adam Back <aba@dcs.ex.ac.uk>
Date: Mon, 27 Oct 1997 18:17:01 +0800
To: tcmay@got.net
Subject: Re: Orthogonality and Disaster Recovery
In-Reply-To: <v03102802b078027ffb91@[207.167.93.63]>
Message-ID: <199710271108.LAA01020@server.test.net>
MIME-Version: 1.0
Content-Type: text/plain




Tim wrote at length about the usefulness of cleanly separating
functionality.

As this applies to pgp5.x, one could apply this idea in the following
way:

- remove pgp file encryption functionality from pgp5.x

- store decrypted emails in the clear in mail folders

- develop PGPdisk for more platforms, and/or market a separate file
  encryption program which only uses symmetric keys.  Integrate
  recovery into that if required, or let the users figure out to copy
  the symmetric storage only "key ring" onto floppies and place in
  fire proof safe themselves.


Problems with this are:

- pgp5.0, pgp5.5 already have this file encryption function built in
  (they might not want to take it out)

- several people are arguing for the need for the company to be able
  to read queued emails encrypted to a company use key when recipient
  is away on holiday, or leaves company, etc.

- some people argue for functionality of having email archives encrypted


Once you start trying to tackle those problems, things get unavoidably
complicated as you attempt to balance the criteria of resistance to
political abuse, resistance to privacy invasion, security, ergonomics,
and meeting user requirements.

I think it's useful to attempt to design systems which balance those
criteria, even though anything which automates any aspect of third
party access to data is inherently dangerous and more prone to
government abuse.

Kent Crispin said sometime ago that cypherpunks (he addressed the
comment to the list readership) should have a go at designing
commercial data recovery protocols.

Even pgp2.x is not that resistant to government abuse as an email
transport.  Governments can demand copies of private keys, governments
can request to be 2nd crypto recipients.  Some governments sooner or
later may even try that with pgp2.x itself.

So I think it is interesting to encourage use of perfect forward
secrecy, at the transport layer, and opportunistically in the pgp
encryption layer.

It is perhaps dangerous, but if people are doing it anyway, it is
useful to examine politically government resistant company storage
recovery, and integration of this into pgp implementations, and
standards even.  Not something cypherpunks would normally consider,
I'm sure, but the functionality of the deployed base is all important,
as is the functionality of standards -- and both of these are to a
large extent influenced by commercial users.

Adam
-- 
Now officially an EAR violation...
Have *you* exported RSA today? --> http://www.dcs.ex.ac.uk/~aba/rsa/

print pack"C*",split/\D+/,`echo "16iII*o\U@{$/=$z;[(pop,pop,unpack"H*",<>
)]}\EsMsKsN0[lN*1lK[d2%Sa2/d0<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<J]dsJxp"|dc`