Series of minor questions about OpenPGP 2

Peter Thomas p4.thomas at
Thu Jan 29 17:22:01 CET 2009

Hi David.

One more thing on this:

On Tue, Jan 27, 2009 at 5:18 AM, David Shaw <dshaw at> wrote:
>> Would gnupg understand these subpackets in a 0x1F signature?
> Yes.  It's a valid key as per the spec, even though no program actually
> generates such a key that I know of.  Note that I can't make that same
> guarantee for other programs.  I suspect they'd work, but you'd have to
> check to be sure.
I had already wrote in another message that I'm trying to do some
interoperability tests (with large keysizes for example).
I'd also like to play with these signature types (0x1F, 0x13 and even
0x18 !) a little bit especially the with the subpackets:
preferred symmetric/hash/compression algorithms, policy URI and key flags
(I think it would even make semantic sense to put them on 0x18s).

Anyway to do this I need to generate those signatures (of course) and
I'd like to use the wonderful code of gnupg :-)
Could you perhaps point me to the useful function names where I can
modify these signatures (0x1F,0x13,0x18) and the functions that are
used to inject subpackages?
Was a great help when you pointed me to the write_header()/etc
functions before :-)

Thanks in advance,

More information about the Gnupg-users mailing list