On Wed, Jul 10, 2019 at 02:44:30PM -0400, Stephen Frost wrote: > Greetings, > > * Bruce Momjian (br...@momjian.us) wrote: > > On Wed, Jul 10, 2019 at 12:38:02PM -0600, Ryan Lambert wrote: > > > > > > what is it that gets stored in the page for > > > decryption use, the nonce or the IV derived from it? > > > > > > > > > I believe storing the IV is preferable and still secure per [1]: "The IV > > > need > > > not be secret" > > > > > > Beyond needing the database oid, if every decrypt function has to > > > regenerate > > > the IV from the nonce that will affect performance. I don't know how > > > expensive > > > the forward hash is but it won't be free. > > > > Well, I think we have three options. We have 3 4-byte integers > > (pg_class.oid, LSN, page-number) that could be concatenated to be the > > IV, we could run those through a hash, or we could run them through the > > encryption function with the secret. > > I didn't see where it was said that using a hash was a good idea in this > context..? Encrypting it with the key looked like it was discussed as a
I didn't either, except it was referenced above as "forward hash". I don't know why that was suggested, which is why I listed it as an option/suggestion. > viable option. I had understood that part of the point of using the Agreed. > table OID and page-number was also so that we didn't have to explicitly > store the result, therefore requiring us to need less space on the page > to make this happen. Yep! -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription +