Re: storing an explicit nonce

Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

> On Tue, Oct 5, 2021 at 1:24 PM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> > On Mon, Oct 4, 2021 at 10:00 PM Stephen Frost <sfrost(at)snowman(dot)net> wrote:
> > > I do want to point out, as I think I did when we discussed this but want
> > > to be sure it's also captured here- I don't think that temporary file
> > > access should be forced to be block-oriented when it's naturally (in
> > > very many cases) sequential. To that point, I'm thinking that we need a
> > > temp file access API through which various systems work that's
> > > sequential and therefore relatively similar to the existing glibc, et
> > > al, APIs, but by going through our own internal API (which more
> > > consistently works with the glibc APIs and provides better error
> > > reporting in the event of issues, etc) we can then extend it to work as
> > > an encrypted stream instead.
> >
> > Regarding this, would it use block-oriented access on the backend?
> >
> > I agree that we need a better API layer through which all filesystem
> > access is routed. One of the notable weaknesses of the Cybertec patch
> > is that it has too large a code footprint,
>
> (sent too soon)
>
> ...precisely because PostgreSQL doesn't have such a layer.

I'm just trying to make our changes to buffile.c less invasive. Or do you mean
that this module should be reworked regardless the encryption?

> But I think ultimately we do want to encrypt and decrypt in blocks, so
> if we create such a layer, it should expose byte-oriented APIs but
> combine the actual I/Os somehow. That's also good for cutting down the
> number of system calls, which is a benefit unto itself.

--
Antonin Houska
Web: https://www.cybertec-postgresql.com