From: "William H. Geiger III" <whgiii@invweb.net>
Date: Thu, 9 Oct 1997 01:35:18 +0800
To: "Jim Russell" <jrussell@syncrypt.com>
Subject: Re: What's really in PGP 5.5?
In-Reply-To: <01bcd407$02595600$2901320a@Polaris.domain>
Message-ID: <199710081728.NAA19596@users.invweb.net>
MIME-Version: 1.0
Content-Type: text/plain



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In <01bcd407$02595600$2901320a@Polaris.domain>, on 10/08/97 
   at 12, "Jim Russell" <jrussell@syncrypt.com> said:

>The swirl of controversy that has arisen since the 2 Oct announcement of
>the PGP Business Security Suite has been quite amazing.  Yet, all of the
>focus has been on what's been *added* to PGP v5.5.  Jon Callas said it
>explicitly:

>>>Corporate Message Recovery is included *only* in PGP for Business
>Security.

>What sense, then, can I make of the following?

>I have been examining the published source code for PGP v5.0 for Personal
>Privacy (note that this is *not* a corporate version), and have
>discovered that this recovery scheme already appears to be in place, in
>some form at least, in that version.

>The following code appears in the published pgp.c, lines 518-537:

>   /*
>    * This is our version of "Commercial Key Escrow".
>    *
>    * A company can set the CompanyKey in the site-wide
>    * configuration file and it will be added to the
>    * recipient list for all encrypted messages.  Then
>    * again, the user can override the setting in their
>    * own pgp.cfg or on the command line.
>    */
>   companyKey = pgpenvGetString (env, PGPENV_COMPANYKEY,
>            NULL, NULL);
>   if (companyKey && *companyKey) {
>    /* Add the company key to the recipient list */
>    e = ringSetFilterSpec (ui_arg->arg.ringset,
>             ringset,
>             companyKey,
>             PGP_PKUSE_ENCRYPT);
>    if (e <= 0)
>     exitUsage(e);
>   }

>This certainly *looks* like the implementation that is being discussed in
>the press release, although I did not find it mentioned in any
>documentation for PGP for Personal Privacy v5.0. The questions this code
>brings to my mind are:

>1.  Does this mean that even the Personal Privacy versions of PGP have a
>message recovery scheme available?  The 2 Oct press release from PGP
>states that the corporate message recovery "transparently integrates with
>*any* version of PGP client software".  (Emphasis mine).

I beleive that this statement refers to the policy enforcement at the SMTP
server. For such a system to work it would have to bounce a message
(according to the policy settings) that was not encrypted with the
corporate key regardless of which version of PGP was used to encrypt the
message.

>2.  If this is implemented via a configuration setting, does it provide
>an opportunity for an attacker to reset the "CompanyKey" to their own
>key?  In the Windows environment, it appears that PGP uses the System
>Registry to hold configuration settings.  Is it possible for me to trick
>someone into running a .REG script that will set the CompanyKey to a key
>to which I hold the private component?

That would seem possiable but you would also have to override the policy
enforcement at the SMTP server. Without examining the product I can't
comment on what mechinism they have in place.

>3.  This appears to me to be quite contradictory to the descriptions
>posted by Jon Callas on 7 Oct.  The procedure that Jon describes, using
>an attribute in the self-signature, would tell an encryptor external to
>The Corporation to use the "skeleton key" on INCOMING mail.  The 5.0 code
>seems to imply an automatic extra recipient on OUTGOING mail, and this
>impression is reinforced by the description of the SMTP server policy
>enforcement in the 2 Oct product description on PGP's web site.  (Let's
>not forget that SMTP is a protocol for OUTGOING mail.) Which is it, or is
>it actually both?

I think that you have a mix of two things here:

1. Encryption of OUTGOING mail using both the Corporate Key and the
Recipiant Key which can be enforced by SMTP policy agent.

2. A preferance flag in the Public Key to inform the user of a public key
to also use the corporate public key when encrypting. There was
disscussion of making use of preferance flags on the Open PGP list for
things like prefered HASH & Key Use.

>Now, I realize that the long-time PGP users, the computer experts who can
>take the source code and recompile the application, could simply remove
>any sections they don't like, or go into the configuration settings and
>change everything to their liking.  However, isn't encryption supposed to
>be moving to a new target audience, the people who use a computer as a
>tool, and don't necessarily know the internals? These are the people who
>need to feel secure using encryption, and magic, invisible encryption to
>a third-party is probably not going to give them warm fuzzy feelings.

I would imagine that they are working from a common code base for all 3
products (shareware, commercial, and business) and merly disable/enable
the various options at compile time. I personally don't mind the code
being there as it lets me see what they are doing in the various versions
(remember Viacrypt never released their source code). I really don't see
this as a problem as it would be quite obvious if the shareware or
commercial version of PGP were adding extra recipiants to an encrypted
message (current PGP format makes this rather hard to hide).

Their seems to be alot of speculation of what PGP 5.5 does or does not do
without anyone actually examining a copy of the program and finding out.
Perhaps a few of us could obtain copys of the program and investegate it
properly. I am willing to boot into NT (shudder) to take a look.

Just as a side note there doesn't seem to be anything PGP 5.5 is doing
that I couldn't get 2.6.x to do with a weekend of codeing. The hard part,
being able to encrypt to multiple recipiants, has been in PGP since day
one.

- -- 
- ---------------------------------------------------------------
William H. Geiger III  http://www.amaranth.com/~whgiii
Geiger Consulting    Cooking With Warp 4.0

Author of E-Secure - PGP Front End for MR/2 Ice
PGP & MR/2 the only way for secure e-mail.
OS/2 PGP 2.6.3a at: http://www.amaranth.com/~whgiii/pgpmr2.html                        
- ---------------------------------------------------------------

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