Horton

Re: storing an explicit nonce

Bruce Momjian <bruce@momjian.us>

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From: Bruce Momjian <bruce@momjian.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Stephen Frost <sfrost@snowman.net>, Ants Aasma <ants@cybertec.at>, Sasasu <i@sasa.su>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-10-07T15:45:35Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Rethink method for assigning OIDs to the template0 and postgres DBs.

  2. pg_upgrade: Preserve database OIDs.

  3. pg_upgrade: Preserve relfilenodes and tablespace OIDs.

  4. Fix for new Boolean node

  5. Improve error handling of HMAC computations

  6. Add macro RelationIsPermanent() to report relation permanence

  7. Enhance nbtree index tuple deletion.

On Thu, Oct  7, 2021 at 10:28:55AM -0400, Robert Haas wrote:
> However, there's also the option of storing a nonce in each page, as
> suggested by the subject of this thread. I think that's probably a
> pretty workable approach, as demonstrated by the patch that started
> this thread. We'd need to think a bit carefully about whether any of
> the compile-time calculations the patch moves to runtime are expensive
> enough to matter and whether any such impacts can be mitigated, but I
> think there is a good chance that such issues are manageable.
> 
> I'm a little concerned by the email from "Sasasu" saying that even in
> XTS reusing the IV is not cryptographically weak. I don't know enough
> about these different encryption modes to know if he's right, but if
> he is then perhaps we need to consider his suggestion of using
> AES-GCM. Or, uh, something else.

I continue to be concerned that a page format change will decrease the
desirability of this feature by making migration complex and increasing
its code complexity.  I am unclear if it is necessary.

I think the big question is whether XTS with db/relfilenode/blocknumber
is sufficient as an IV without a nonce that changes for updates.

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

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