Subject: More questions and comments on rfc2440bis-12

From: Ben Laurie <[email-masked]>
Date: Wed, 23 Feb 2005 11:37:19 +0000

In 5.2.1:

"0x10: Generic certification of a User ID and Public Key packet."

Does this mean that the signature is over the User ID packet and the 
Public Key packet, concatenated, in that order? Or what?

Also, what on earth does:

        Note that all PGP "key signatures" are this type of
        certification.

mean?

In 5.2.2:

    "The data being signed is hashed, and then the signature type and
    creation time from the signature packet are hashed (5 additional
    octets)."

is unclear, suggest:

"The concatenation of the data to be signed, the signature type and
creation time from the signature packet (5 additional octets) is hashed."

-- 
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"There is no limit to what a man can do or how far he can go if he
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From: David Shaw <[email-masked]>
Date: Fri, 25 Feb 2005 11:27:16 -0500

> Public Key packet, concatenated, in that order? Or what?

5.2.1 is just an overview.  The nitty-gritty on how to make each type
is specified in 5.2.4. Computing Signatures.

>        Note that all PGP "key signatures" are this type of

PGP doesn't generate 0x11, 0x12, or 0x13 signatures, and when it
encounters them treats them all as if they were 0x10.

By default GnuPG generates 0x10, but the user can request another
type.  Also by default GnuPG ignores 0x11 signatures completely, but
treats treats 0x12 and 0x13 the same as 0x10.

David

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From: Ben Laurie <[email-masked]>
Date: Fri, 25 Feb 2005 17:18:14 +0000

> encounters them treats them all as if they were 0x10.

When you say "PGP" you mean, presumably, some version(s) of the software 
- which? I presume modern ones do generate them all?

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From: David Shaw <[email-masked]>
Date: Fri, 25 Feb 2005 13:11:28 -0500

> - which? I presume modern ones do generate them all?

All versions I've ever seen, including 2, 5, 6, 7, and 8, and all
sub-versions of that list.

I see 0x11, 0x12, and 0x13 as sort of a vestigal tail in OpenPGP.
They're not really useful for much, and are pretty much ignored.
Certainly 0x12 doesn't have less validity than 0x13 in the usual
definition of the web of trust.

David

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From: Jon Callas <[email-masked]>
Date: Fri, 25 Feb 2005 16:08:20 -0800

On other certification types:

Apart from what David said about GnuPG, no one has ever done any sort 
of certification other than the 0x10 certification signatures. (By that 
I mean that there's never been a program that actually went to the 
trouble of creating a UI that effectively said, "How good do you think 
this certification is?")

At one point, we removed them from OpenPGP because no one used them. 
They were put in because the working group liked the expressiveness of 
the language even if no one was expressing themselves that way. I think 
that discussion is still valid and don't see a reason to change it. The 
different degrees of certification are in the OpenPGP language because 
we as a group think they should be there.

	Jon

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From: Ben Laurie <[email-masked]>
Date: Sat, 26 Feb 2005 12:45:16 +0000

Jon Callas wrote:
> Apart from what David said about GnuPG, no one has ever done any sort of 
> certification other than the 0x10 certification signatures. (By that I 
> mean that there's never been a program that actually went to the trouble 
> of creating a UI that effectively said, "How good do you think this 
> certification is?")
> 

OK, then the explanation could perhaps be improved.