Horton

Re: [Proposal] Table-level Transparent Data Encryption (TDE) and Key Management Service (KMS)

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>, Joe Conway <mail@joeconway.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Antonin Houska <ah@cybertec.at>, Haribabu Kommi <kommi.haribabu@gmail.com>, "Moon, Insung" <Moon_Insung_i3@lab.ntt.co.jp>, Ibrar Ahmed <ibrar.ahmad@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2019-07-11T19:54:20Z
Lists: pgsql-hackers

Commits

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  1. Revamp the WAL record format.

On Thu, Jul 11, 2019 at 03:47:50PM -0400, Robert Haas wrote:
> On Tue, Jul 9, 2019 at 10:43 AM Bruce Momjian <bruce@momjian.us> wrote:
> > FYI, pg_upgrade already preserves the pg_class.oid, which is why I
> > recommended it over pg_class.relfilenode:
> 
> I think it's strange that pg_upgrade does not preserve the
> relfilenode.  I think it would probably make more sense if it did.
> 
> Anyway, leaving that aside, you have to be able to read pg_class to
> know the OID of a table, and you can't do that in recovery before
> reaching consistency. Yet, you still need to be able to modify disk
> blocks at that point, to finish recovery. So I can't see how any
> system that involves figuring out the nonce from the OID would ever
> work.
> 
> If we end up with random nonces, we're going to have to store them
> someplace - either in some unencrypted portion of the disk blocks
> themselves, or in a separate fork, or someplace else. If it's OK for
> them to predictable as long as they vary a lot, we could derive them
> from DBOID + RELFILENODE + FORK + BLOCK, but not from DBOID + RELOID +
> FORK + BLOCK, because of the aforementioned recovery problem.

Later in this thread, we decided that the page LSN was the best option
as a nonce because it changes every time the page chages.  (We will
enable wal_log_hints.)  We will not encrypt the first 16 bytes of the
page so it can be used for the nonce. (AES block ciphers are use 16-byte
blocks.)

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
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