Domain Key support

["John Nietzsche" <john.nietzsche@gmail.com>]

Dear list members,

i am considering adding dns records for domainkeys. I would like to
implement email authentication using djbdns, qmail and the end user
email utilities. I wonder if anyone in this list have done so before?
I have a mixture of windows and unix box. Does their mua support such
scenario? I mean: will a user receiving/sending email from a
desktop/workstation using Firefox or even native MS mua be able to
encrypt/decrypt messages he sent/receives?

Thanks a lot for your time and cooperation.

Best regards.