[ietf-dkim] detecting header mutations after signing

[Graham Murray]

"John R. Levine" <johnl at iecc.com> writes:
>
> DKIM support in an MUA?  Yuck.
>
> It's likely to be a long time before any MUA I use does anything with 
> DKIM, since I am not a fan of filtering mail while reading it. 

An MUA does not have to do filtering in order to support DKIM. It could
display the Authentication Results header, or take some action depending
on whether there is a valid DKIM signature - in a similar way that some
web browsers will turn the URL bar green when the site presents a valid
'extended validation' certificate.