| From: | Nico Williams <nico(at)cryptonector(dot)com> |
|---|---|
| To: | Joe Conway <mail(at)joeconway(dot)com> |
| Cc: | Bruce Momjian <bruce(at)momjian(dot)us>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com>, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, "Moon, Insung" <Moon_Insung_i3(at)lab(dot)ntt(dot)co(dot)jp>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: [Proposal] Table-level Transparent Data Encryption (TDE) and Key Management Service (KMS) |
| Date: | 2018-06-20 22:28:43 |
| Message-ID: | 20180620222842.GG4200@localhost |
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| Lists: | pgsql-hackers |
On Wed, Jun 20, 2018 at 06:19:40PM -0400, Joe Conway wrote:
> On 06/20/2018 05:12 PM, Bruce Momjian wrote:
> > On Mon, Jun 18, 2018 at 11:06:20AM -0400, Joe Conway wrote:
> > Even if they are encrypted with the same key, they use different
> > initialization vectors that are stored inside the encrypted payload, so
> > you really can't identify much except the length, as Robert stated.
Definitely use different IVs, and don't reuse them (or use cipher modes
where IV reuse is not fatal).
> The more you encrypt with a single key, the more fuel you give to the
> person trying to solve for the key with cryptanalysis.
With modern 128-bit block ciphers in modern cipher modes you'd have to
encrypt enough data to make this not a problem. On the other hand,
you'll still have other reasons to do key rotation. Key rotation
ultimately means re-encrypting everything. Getting all of this right is
very difficult.
So again, what's the threat model? Because if it's sysadmins/DBAs
you're afraid of, there are better things to do.
Nico
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