On Tue, Mar 17, 2026 at 9:21 AM Nico Williams <[email protected]> wrote:

> On Tue, Mar 17, 2026 at 08:56:32AM -0700, Eric Rescorla wrote:
> > On Tue, Mar 17, 2026 at 8:01 AM Viktor Dukhovni <[email protected]>
> > wrote:
> > > FWIW, I just don't have the energy to object to every well-meaning, but
> > > counterproductive proposal.  And it can be uncomfortable to uphold a
> > > minority view...
> > >
> > > I agree that reuse of keyshares across multiple connections should
> > > generally be avoided, which is the status-quo in RFC8446, but there are
> > > sometimes just exceptions.  An unenforceable MUST NOT may feel like
> > > progress, but it may do more harm than good.
> >
> > "May" is doing a lot of work here.
> >
> > Do you have some actual substantive argument to offer?
>
> The substantive argument is: if it isn't easy to even implement this
> requirement, and it's not fatal to security to not implement it, then
> why bother stating this requirement when a recommendation suffices?


Well, Viktor didn't offer this argument, but in any case, this argument
is wrong. It is trivial to implement this requirement: just generate a
fresh key for each connection. In fact, it is more work to not implement it.

What is not easy is to *enforce* this requirement, but as nobody is
proposing to enforce it and in fact the PR tells you not to, the difficulty
of enforcing it is not relevant.

-Ekr
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