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

On Wed, Jul 31, 2019 at 04:11:03PM +0900, Masahiko Sawada wrote:
> On Wed, Jul 31, 2019 at 5:48 AM Bruce Momjian <bruce@momjian.us> wrote:
> > I am thinking for the heap/index IV, it would be:
> >
> >         uint64 lsn;
> >         unint32 page number;
> >         /* only uses 11 bits for a zero-based CTR counter for 32k pages */
> >         uint32 counter;
> >
> 
> +1
> IIUC since this would require to ensure uniqueness by using key+IV we
> need to use different keys for different relations. Is that right?

No.  My other email states that the LSN is only used for a single
relation, so there is no need for the relfilenode in the nonce.  A
single LSN writing to multiple parts of the relation generates a unique
nonce since the page number is also part of the nonce.

> > and for WAL it would be:
> >
> >         uint64 segment_number;
> >         uint32    counter;
> >         /* guarantees this IV doesn't match any relation IV */
> >         uint32   2^32-1 /* all 1's */
> 
> I would propose to include the page number within a WAL segment to IV
> so that we can encrypt each WAL page with the counter always starting
> from 0. And if we use different encryption keys for tables/indexes and

What is the value of that?

> And if we use different encryption keys for tables/indexes and
> WAL I think we don't need 2^32-1.

I see little value to using different encryption keys for tables/indexes
and WAL.

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

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