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

2008-05-12 13:39:02

At 1:43 PM -0500 5/12/08, Timothy J Miller wrote:
On May 12, 2008, at 11:49 AM, Paul Hoffman wrote:

When feasible, sending and receiving agents SHOULD inform senders (prior
to transmission) and recipients of the relative cryptographic strength of
messages and SHOULD provide a warning if weak algorithms or key sizes are
used.

I'm lost here. Using the protocol described in the document, how would I send such information? How would I send such a warning?

Yet similar advice exists elsewhere in the cert handling spec:

"""
A receiving agent SHOULD provide some explicit alternate processing of the message if this comparison fails, which may be to display a message that shows the recipient the addresses in the certificate or other certificate details.
"""  (ref: sec 3)

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.

Are you saying that this should come out as well, since your objection to the RFC advising implementors to warn users re: key strength clearly also applies to the RFC advising implementors re: an email mismatch?

Nope. I have nothing against advising implementers. Heck, I've written a lot of the text that does that. What I object to is a SHOULD-level "inform" or "provide a warning" when we have no protocol-standard way of doing so.