Partial length headers

David Shaw dshaw at
Mon Nov 24 13:29:45 CET 2003

On Fri, Nov 21, 2003 at 08:16:20PM -0500, Hasnain Mujtaba wrote:
> Thanks. A couple more questions:
> Looking at the pgpdump of an encrypted file, I see that GPG uses the
> Symmetrically Encrypted and MDC Packet (tag 18). 
> I cannot find this tag in RFC 2440. Where can I get more information on
> this tag type and its internal structure? I am trying to understand how
> partial length chunks are built. Are these partial chunks nested within
> the outer Symm Encrypted and MDC Packet? What is the name of the
> outer-most packet? Is it the Symmetrically Encrypted packet? 

The MDC packet is defined in 2440bis - the draft that will eventually
replace RFC-2440.  You can get the latest draft at


More information about the Gnupg-users mailing list