Re: S/MIME v3.2 IDs key size text (resend, no signature)

On May 12, 2008, at 3:19 PM, Paul Hoffman wrote:

> Only somewhat similar. Tony's proposed changes has a "SHOULD inform"  
> and a "SHOULD provide a warning". The quoted test is "SHOULD provide  
> alternate processing" which may be displaying a message. That's a  
> big difference.
Yet the very next paragraph says:

"""
A receiving agent SHOULD display a subject name or other certificate  
details when displaying an indication of successful or unsuccessful  
signature verification.
"""

Sounds the same to me.

Here's the thing:  You're advocating interpreting the spec as purely a  
protocol spec.  If that's what you're after, then that's a bigger  
issue than trading barbs over key length recommendations.  There are a  
number of clauses that require UI implementation that need to be  
struck out (or at least moved to the security considerations section).
But here's my problem with that thinking:  S/MIME isn't just a  
protocol, it's a ceremony.  There's an fundamental UI aspect to  
ceremonies.  This needs to be dealt with properly and *prominently* or  
we'll end up with implementations that don't just *allow* bad things  
to be done, but that *mislead users* into thinking things are true  
about messages that just aren't.
Moving all UI-related issues or security related recommendations to a  
separate section lowers their visibility, and that's not a good thing  
IMHO.
-- Tim

smime.p7s
Description: S/MIME cryptographic signature