Virus-checking software flagging GNUpg signatures?

[Simon Josefsson]

On Fri, 18 Jan 2002, Lars Hecking wrote:

> > Another "practical" problem with PGP/MIME is that MIME headers is 
> > sometimes changed in transit or by mail servers which breaks the 
> > signature.
> 
>  Such mail servers are broken. sendmail was suffering from this
>  particular bug, but it was fixed in 8.9.3. Last time I checked
>  (which was a while ago, admittedly), courier-mta exhibited this
>  broken behaviour as well.

Yet another problem: Forwarding a signed multipart message inside
message/rfc822 usually changes the MIME delimiters used within the signed
part as well, thus rendering the signature invalid.  RFC 3156 doesn't say
anything about this, RFC 2480 touches on a related topic but is silent on
MUA forwarding.  One solution would be to require MUAs to not modify MIME
delimiters inside signed parts -- does anyone know if any MUA takes this
path?

If you are on ietf-openpgp, you can take the position that these programs
are "broken", but if you want to get something done in the real world, it
isn't as simple IMHO.