Subject: Comments on draft-ietf-openpgp-rfc2440bis-12

From: Ben Laurie <[email-masked]>
Date: Sat, 15 Jan 2005 20:54:51 +0000

3.2 (MPI) doesn't specify what the unused bits should be set to. This 
may be deliberate but I think it should either say they MUST be zero 
(which I prefer) or that their content is unspecified.

4.2 refers to Content Tags, but 4.3 calls them Packet Tags.

-- 
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From: David Shaw <[email-masked]>
Date: Sat, 15 Jan 2005 16:38:32 -0500

> (which I prefer) or that their content is unspecified.

I'm not completely sure what you are referring to here.  Do you mean
the difference (given an MPI of value "1") between [00 01 01] and [00
01 02] ?  The 0x02 bit of the 3rd octet?

David

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From: David Shaw <[email-masked]>
Date: Sat, 15 Jan 2005 16:57:12 -0500

> 01 02] ?  The 0x02 bit of the 3rd octet?

Er, I meant [00 01 03], but the question still holds.  Are you
referring to the 0x02 bit of the last octet?

David

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From: Ben Laurie <[email-masked]>
Date: Sun, 16 Jan 2005 08:03:54 +0000

> referring to the 0x02 bit of the last octet?

Yes.

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From: David Shaw <[email-masked]>
Date: Sun, 16 Jan 2005 11:26:23 -0500

> >referring to the 0x02 bit of the last octet?

I see.  I think that the draft does indirectly specify that the unused
bits are 0.  In section 3.2 it states "These octets form a big-endian
number; a big-endian number can be made into an MPI by prefixing it
with the appropriate length."  [00 01 03] would violate that
statement, since the big-endian number would be 3, rather than 1.

I certainly don't have any objection to making it more explicit than
that, though.

David

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From: Ben Laurie <[email-masked]>
Date: Mon, 17 Jan 2005 17:53:18 +0000

> statement, since the big-endian number would be 3, rather than 1.

I don't think that would be an unambiguous requirement, since the 
implementation might also measure length in bits.

> I certainly don't have any objection to making it more explicit than

Good.