Re: storing an explicit nonce

Greetings,

On Tue, Oct 12, 2021 at 17:49 Ants Aasma <ants(at)cybertec(dot)at> wrote:

>
> On Wed, 13 Oct 2021 at 00:25, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>
>> On Tue, Oct 12, 2021 at 11:21:28PM +0300, Ants Aasma wrote:
>> > On Tue, 12 Oct 2021 at 16:14, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
>> >
>> > Well, how do you detect an all-zero page vs a page that encrypted
>> to all
>> > zeros?
>> >
>> > Page encrypting to all zeros is for all practical purposes impossible
>> to hit.
>> > Basically an attacker would have to be able to arbitrarily set the whole
>> > contents of the page and they would then achieve that this page gets
>> ignored.
>>
>> Uh, how do we know that valid data can't produce an encrypted all-zero
>> page?
>>
>
> Because the chances of that happening by accident are equivalent to making
> a series of commits to postgres and ending up with the same git commit hash
> 400 times in a row.
>

And to then have a valid checksum … seems next to impossible.

Thanks,

Stephen

>