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

On Thu, Jul 25, 2019 at 11:30:55PM -0400, Alvaro Herrera wrote:
> On 2019-Jul-25, Alvaro Herrera wrote:
>
> > > Uh, there are no known attacks on AES with known plain-text, e.g., SSL
> > > uses AES, so I think we are good with encrypting everything after the
> > > first 16 bytes.
> >
> > Well, maybe there aren't any attacks *now*, but I don't know what will
> > happen in the future. I'm not clear what's the intended win by
> > encrypting the all-zeroes page hole anyway. If you leave it
> > unencrypted, the attacker knows the size of the hole, as well as the
> > size of the tuple data area and the size of the LP array. Is that a
> > side-channer that leaks much?
>
> This answer https://crypto.stackexchange.com/a/31090 is interesting for
> three reasons:
>
> 1. it says we don't really have to worry about cleartext attacks, at
> least not in the immediate future, so encrypting the hole should be OK;
>
> 2. it seems to reinforces a point I tried to make earlier, which is that
> reusing the IV a small number of times is *not that bad*:

I think using LSN and page number, we will _never_ reuse the IV, except
for cases like promoting two standbys, which I think we have to document
as an insecure practice.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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