Series of minor questions about OpenPGP 1

Peter Thomas p4.thomas at
Mon Jan 26 17:22:11 CET 2009

Hi David.

On Mon, Jan 26, 2009 at 3:52 PM, David Shaw <dshaw at> wrote:
>> I'm currently reading RFC4880 and I think I have many minor questions... is the gnupg-users list the right place to ask? Or is there any better place?
> Look for the ietf-openpgp mailing list at
I'll have a look at this, but as at least some of my questions seem to
be gnupg specific I'll continue to ask some stuff here.

>> 1) In chapter on page 13 it says that the octet can have values "255 or 254". Is there any difference between the two?
> Yes, see section 5.5.3 for the exact details, but in general 254 indicates that there is a SHA-1 hash of the secret data included.  This is to prevent a secret key tampering attack.
Ah, thanks. So I'd should be 254 for better security of the private key, right?

>> What's the reason for this? I mean the RFC recommends to use the new packet format. Can I change that default behaviour? And if I have a key, that's already used and signed by others, could I convert it to using the new format?
> You could convert it, but there is little point.
Uhm, I just wanted to follow the recommendation of the RFC ;-)

>The function of a packet is the same no matter what.
So all other signatures would still be valid?

But there is probably no function in gnupg to do this conversion, is it?


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