From: Andrew Bromage <bromage@cs.mu.oz.au>
Date: Sun, 19 Oct 1997 05:32:40 +0800
To: kent@bywater.songbird.com (Kent Crispin)
Subject: Re: Is PGP still private?
In-Reply-To: <19971018092636.45297@bywater.songbird.com>
Message-ID: <199710182122.HAA24989@mundook.cs.mu.OZ.AU>
MIME-Version: 1.0
Content-Type: text/plain



G'day all.

Kent Crispin wrote:

> Your reencryption scheme fails because of the management of the short
> term encryption keys, among other things.  Here's another approach I
> will toss out, without thinking through:
> 
> How about formalizing superencryption, or tunneling? That is, treat
> CMR traffic as a transport medium for messages that are themselves
> already encrypted.  The "key" idea here is to allow layering of non
> CMR traffic over CMR traffic.  All the code for both is obviously
> already in PGP, with a little glue and perhaps some minor protocol
> mods...

If we start considering that, could I suggest making the system
_completely_ flexible?

The sort of things I'm thinking of include:  Allow any object to be
encrypted using conventional encryption (including conventional
encryption keys) or signed, allow any conventional encryption key to
be public-key encrypted or split, conjunction/disjunction of two
conventional keys, etc.

Disadvantages:

	- Greatly complicates the decryption process.  In particular,
	  decrypted streams must be fed back into PGP.

	- Difficult for an end-user to specify what combination of
	  features they want.

	- This working group would be around for years arguing about
	  details. :-)

Advantages:

	- Allows PGP to be used for lots of things that we haven't
	  thought of yet.

	- File format could be considerably simplified, if we could
	  scrap the old format.  (Unrealistic, but what the hell.)

Cheers,
Andrew Bromage