Subject: [Uta] Alissa Cooper's Discuss on draft-ietf-uta-tls-bcp-09: (with DISCUSS and COMMENT)

From: "Alissa Cooper" <[email-masked]>
Date: Tue, 17 Feb 2015 11:49:51 -0800

Alissa Cooper has entered the following ballot position for
draft-ietf-uta-tls-bcp-09: Discuss

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DISCUSS:
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Thanks for all your work on this.

I have a quick question about how we expect this document to be used
within the IETF. I note that the bulk of the requirements/recommendations
are directed at implementers, not protocol designers/specs. And Section
4.2.1 also says:

"This document does not change the mandatory-to-implement TLS cipher
   suite(s) prescribed by TLS or application protocols using TLS. ...
   Implementers should consider the interoperability gain against the
   loss in security when deploying that cipher suite.  Other application
   protocols specify other cipher suites as mandatory to implement
   (MTI)."

So my question is whether we should consider this document effectively
silent about the choice of cipher suites to be used when we standardize a
new application protocol in the IETF, or an update to an existing
protocol. That is the impression that I get from the text right now, and
it doesn't quite match the way we've been using/citing the document in
some recent discussions of other drafts. On the other hand, if we're
expecting new or updated application protocol specs to conform to or take
into account the recommendations in this document, I think that should be
made more clear.

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COMMENT:
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-- Sec 4.1:
128-bit ciphers are expected to remain secure for at least several years,
and
      256-bit ciphers "until the next fundamental technology
      breakthrough".
    
Is the quoted text quoting something? If not, why is it in quotes?

-- Sec 5:
Although the list here is non-exhaustive, it seems odd to me that no DTLS
examples are listed.