Greetings, * Bruce Momjian (br...@momjian.us) wrote: > On Mon, Jul 8, 2019 at 11:18:01AM -0400, Joe Conway wrote: > > On 7/8/19 10:19 AM, Bruce Momjian wrote: > > > When people are asking for multiple keys (not just for key rotation), > > > they are asking to have multiple keys that can be supplied by users only > > > when they need to access the data. Yes, the keys are always in the > > > datbase, but the feature request is that they are only unlocked when the > > > user needs to access the data. Obviously, that will not work for > > > autovacuum when the encryption is at the block level. > > > > > If the key is always unlocked, there is questionable security value of > > > having multiple keys, beyond key rotation. > > > > That is not true. Having multiple keys also allows you to reduce the > > amount of data encrypted with a single key, which is desirable because: > > > > 1. It makes cryptanalysis more difficult > > 2. Puts less data at risk if someone gets "lucky" in doing brute force > > What systems use multiple keys like that? I know of no website that > does that. Your arguments seem hypothetical. What is your goal here?
Not sure what the reference to 'website' is here, but one doesn't get certificates for TLS/SSL usage that aren't time-bounded, and when it comes to the actual on-the-wire encryption that's used, that's a symmetric key that's generated on-the-fly for every connection. Wouldn't the fact that they generate a different key for every connection be a pretty clear indication that it's a good idea to use multiple keys and not use the same key over and over..? Of course, we can discuss if what websites do with over-the-wire encryption is sensible to compare to what we want to do in PG for data-at-rest, but then we shouldn't be talking about what websites do, it'd make more sense to look at other data-at-rest encryption systems and consider what they're doing. Thanks, Stephen
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