Subject: Re: questions: packet tag or content tag (4.3), what is placed in hashed subpacket field (5.2.3), critical bit (5.2.3.1), default user id (5.2.3.3)

From: [email-masked]
Date: Mon, 22 May 2000 08:36:36 -0700

> so is the signing key id the only subpacket that is allowed to go in
> the unhashed area?

No, anything which might reasonably be considered to be "advisory"
and not security critical could go there.  For example the URL where
the cert can be found.  I don't know if there is an exhaustive list.
The point is that the software needs to be aware that material in the
unhashed region is not authenticated and could have been tampered with.

> also, for a given subpacket type, can instances of
> that subpacket appear in either the hashed subpacket field or the
> unhashed subpacket field, or is it a mutually exclusive situation?

I don't see any problem in allowing that.

Hal

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From: "William H. Geiger III" <[email-masked]>
Date: Tue, 23 May 2000 07:29:01 -0500

In <[email-masked]>, on 05/22/00 

>No, anything which might reasonably be considered to be "advisory" and
>not security critical could go there.  For example the URL where the cert
>can be found.  I don't know if there is an exhaustive list. The point is
>that the software needs to be aware that material in the unhashed region
>is not authenticated and could have been tampered with.

>I don't see any problem in allowing that.

As an open question to list members:

What do you consider the proper response of OpenPGP software (client &
server) when an established key (ie a key on the server or users keyring)
is "updated" and unhashed data has been changed?

Take the example:

Software A lets the user enter on his key the prefered URL to obtain his
key on the self-sig for his key and the software stores it in an unhashed
subpacket.

The user distributes his key (other users, servers, ...ect).

Software A also allows the user to change this at a later date without
creating a new signature.

The user distributes this "updated" key.

How should the receiving software treat this "updated" data?

-- Ignore the "new" data

-- Accept the "new" data in place of the old data

-- Notify the receiver that there is "new" data and let him decide

-- ....?

-- 
---------------------------------------------------------------
William H. Geiger III      http://www.openpgp.net  
Geiger Consulting    

Data Security & Cryptology Consulting
Programming, Networking, Analysis
 
PGP for OS/2:               http://www.openpgp.net/pgp.html
E-Secure:                   http://www.openpgp.net/esecure.html
---------------------------------------------------------------

---

From: [email-masked]
Date: Fri, 26 May 2000 15:07:54 +0900

From: "William H. Geiger III" <[email-masked]>
Subject: Re: questions: packet tag or content tag (4.3), what is placed in hashed subpacket field (5.2.3), critical bit (5.2.3.1
Date: Tue, 23 May 2000 07:29:01 -0500
Message-ID: <[email-masked]>

...

> is "updated" and unhashed data has been changed?

it seems to me that this might be handled in a number of ways depending
on the particular situation:

  -determined by "local" policy (the client or server has a policy which it
   follows)

  -determined by "key" policy (a policy is determined from some signed
   portion of the key)