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Subject: Re: Enquiry about TDE with PgSQL
From: Rainer Duffner <rainer@ultra-secure.de>
In-Reply-To: <aQZXgEH5pvEwKq+O@customer.dllstxx1.isp.starlink.com>
Date: Sat, 1 Nov 2025 21:07:01 +0100
Cc: pgsql-general@postgresql.org
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To: Ken Marshall <ktm@rice.edu>
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> Am 01.11.2025 um 19:54 schrieb Ken Marshall <ktm@rice.edu>:
>=20
> +1 from me for having TDE in-core or available as an extension
>=20
> The security auditors that I have worked with have been increasingly
> unwilling to actual evaluate the merits of an implementation or =
perhaps
> no longer have the knowledge or skills needed. This is a needed
> checkbox to allow PostgreSQL to be deployed in those environments.
>=20
>=20


Do you actually have HSMs with your TDE (assuming you use it elsewhere?
We run, for a customer, an Oracle DataGuard configuration with TDE with =
a HSM.

We have a support-contract with a 3rd party company that helps us with =
the more obscure problems on Oracle that we don=E2=80=99t encounter =
every day and they told us of all their clients (banks, insurance =
companies), we are the only ones with TDE. They loath working with it =
;-)

There=E2=80=99s apparently another non-disclosed customer that uses it.

It may be that a lot of people now use =E2=80=9Ecloud HSMs=E2=80=9C - =
but I=E2=80=99m a bit of a purist for these kinds of things in that I =
believe that unless you own the hardware (HSMs are usually tamper-proof =
enough so you can deploy them in 3rd-party datacenters that aren=E2=80=99t=
 your own), you don=E2=80=99t really control the keys.

In our case, the databases are backed up with rman to an NFS share that =
is provided by a virtualized linux server - the severs itself are =
hardware.

If you don=E2=80=99t have TDE, your backups aren=E2=80=99t encrypted and =
they end up on the veeam server like everything else, where an admin =
could copy them somewhere else and potentially take them elsewhere.

With the HSM, we don=E2=80=99t actually know the secret to decrypt the =
data (there may be a way to get it, I don=E2=80=99t know). We know the =
secret to unseal the wallet (that sits on the HSM, I believe) so that =
the database actually mounts and starts.

It=E2=80=99s pretty bullet-proof (I believe there=E2=80=99s techniques =
to prevent sniffing out the secret from RAM and HSMs usually implement =
those in their client software).
In fact, it=E2=80=99s so bullet-proof that should you lose the keys on =
the HSM, your data is gone if you have no other backups or backups of =
the HSM.=20

If the amount of data is small enough, you can GPG encrypt a =
=E2=80=9Enormal=E2=80=9C full dump - but that become unfeasible as =
database size grows.