Re: storing an explicit nonce

On Thu, Oct  7, 2021 at 11:32:07PM -0400, Stephen Frost wrote:
> Part of the meeting was specifically about "why are we doing this?" and
> there were a few different answers- first and foremost was "because
> people are asking for it", from which followed that, yes, in many cases
> it's to satisfy an audit or similar requirement which any of the
> proposed methods would address.  There was further discussion that we

Yes, Cybertec's experience with their TDE patch's adoption supported
this.

> could address *more* cases by providing something better, but the page
> format changes were weighed against that and the general consensus was
> that we should attack the simpler problem first and, potentially, gain
> a solution for 90% of the folks asking for it, and then later see if
> there's enough interest and desire to attack the remaining 10%.

It is more than just the page format --- it would also be the added
code, possible performance impact, and later code maintenance to allow
for are a more complex or two different page formats.

As an example, I think the online checksum patch failed because it
wasn't happy with that 90% and went for the extra 10% of restartability,
but once you saw the 100% solution, the patch was too big and was
rejected.

> As such, it's just not so simple as "what is 'secure enough'" because it
> depends on who you're talking to.  Based on the collective discussion at
> the meeting, XTS is 'secure enough' for the needs of probably 90% of
> those asking, while the other 10% want better (an AEAD method such as
> GCM or GCM-SIV).  Therefore, what should we do?  Spend all of the extra
> resources and engineering effort to address the 10% and maybe not get
> anything because of the level of difficulty, or go the simpler route
> first and get the 90%?  Through that lense, the choice seemed reasonably
> clear, at least to me, hence why I agreed that we should work on an XTS
> based approach first.

Yes, that was the conclusion.  I think it helped to have the discussion
verbally with everyone hearing every word, rather than via email where
people jump into the discussion not hearing earlier points.

-- 
  Bruce Momjian  <bruce@momjian.us>        https://momjian.us
  EDB                                      https://enterprisedb.com

  If only the physical world exists, free will is an illusion.