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

On Tue, Jul  9, 2019 at 10:34:06AM +0200, Tomas Vondra wrote:
> > I think the issues is that we can't use a _counter_ for the nonce since
> > each page-0 of each table would use the same nonce, and each page-1,
> > etc.  I assume we would use the table oid and page number as the nonce.
> > We can't use the database oid since we copy the files from one database
> > to another via file system copy and not through the shared buffer cache
> > where they would be re encrypted.  Using relfilenode seems dangerous.
> > For WAL I think it would be the WAL segment number.  It would be nice
> > to mix that with the "Database system identifier:", but are these the
> > same on primary and replicas?
> > 
> 
> Can't we just store the nonce somewhere? What if for encrypted pages we
> only use/encrypt (8kB - X bytes), where X bytes is just enough to store
> the nonce and maybe some other encryption metadata (key ID?).

Storing the nonce on each 8k page is going to add complexity, so I am
trying to figure out if it is a security requirement.

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

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