Re: [saag] Section 2.9: was Re: AD review of draft-iab-crypto-alg-agility-06

[Viktor Dukhovni <[e-mail]>]

On Wed, Sep 02, 2015 at 06:06:45PM -0400, Barry Leiba wrote:

> (Responding to the thread in general, not to Viktor's note in particular.)
> 
> I honestly don't see why this issue is relevant to agility at all, and
> I would just strike the mention altogether, as I don't think it
> affects the point that we need to have the ability to change
> algorithms baked into the protocol and designed into the software.
> 
> The point of OS is to negotiate the best security we can, and be
> willing to accept a certain minimal security level, where the
> definition of what's minimally acceptable will change from one
> situation to another.
> 
> Algorithm agility can help us achieve that, and that might be worth
> saying.  But whether in a particular OS situation we care willing to
> negotiate something that we'd otherwise consider deprecated is a
> question unto itself, not one that guidance on algorithm agility needs
> to discuss.

Barry's suggestion works for me.  Perhaps this document need not
be the one to clarify cipher deprecation for OS.

But if it does, some text to make it clear that OS is about using
the *strongest available* crypto, not weak crypto.  But crypto
weaker than would otherwise be acceptable, may be acceptable with
OS for some time to facilitate interoperability with legacy systems.

It can be a sentence or two, just enough to not give the impression
that weak crypto is preferred with OS.

-- 
	Viktor.