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

On 2019-Jul-27, Bruce Momjian wrote:

> 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.

Actually, why is it an insecure practice?  If you promote two standbys,
then the encrypted pages are the same pages, so it's not two different
messages with the same key/IV -- they're still *one* message.  And as
soon as they start getting queries, they will most likely diverge
because the LSNs of records after the promotion will (most likely) no
longer match.  It takes one different WAL record length for the
"encryption histories" to diverge completely ...

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
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