[ext] Re: Display info about S/MIME signature

[Bastian]

IIUC, you would like to see which certificates have been used while 
reading the mail. Sometime I also need such extra info, and I was 
struggling to get the info. So I dove again a bit into it.

On 13Oct22 08:26+0200, Ralf Hildebrandt via Mutt-users wrote:
> > gpgsm --list-keys ralf.hildebrandt at charite.de
> > 
> > would give you all information about the key, including ID (which is the
> > last part of the fingerprint), serial etc.
> 
> Yeah, that's awesome. Exactly what I need!

gpgsm actually lists the content of your gnupg pubring. So you need to 
have the certificate already added to this database. Otherwise it is not 
finding the cert. And also this seems to be unrelated to the mail which 
is currently open in mutt's pager.

Another solution might be:
In mutt (pager or index view), you can use the pipe_message function 
(default keybind is |) and pipe the mail to:

--- paste: ---
openssl smime -pk7out | openssl pkcs7 -print_certs -text|less
--- eop ---

This command should work on smime multipart emails. It extracts the 
attached certificates and prints them. So you can see, which 
certificate (and which CA) were used to sign this particular email.

I think it is straight forward to bind this function to a key. It might 
also be possible to modify the config option 'smime_verify_commmand'.
But that did not work in my tests, mutt claimed verification is not 
successful even though openssl returned successfully.


Cheers,
-- 
Bastian