On Fri, 2005-11-18 at 08:57 +0000, Stephen Farrell wrote: > > > The "From:" header should not be signed if it contains more than one > > sending address. > > Exactly. Or whatever the correct variant might be e.g. I think > I'd prefer "don't sign at all if there's >1 From address" so that > we have fewer chances for verifier misinterpretation, but that > might be my security-and-not-email heritage coming to the fore. > > Does anyone see such a statement as causing a problem? I could > imagine that moving from signing anything, to only signing some > mail messages might be either a good or a bad idea.
Including the From header field within the signature hash makes a great deal of sense. Not including it does not. The problem was dealing with the effects of the _only_ policy (o=!) that prevents spoofing. This policy does not allow not signing. Half measures are thwarted by mechanisms that hold the email-address accountable. Any exception becomes the mode that spammers will use. -Doug _______________________________________________ ietf-dkim mailing list http://dkim.org
