Re: XTS cipher mode for cluster file encryption - Mailing list pgsql-hackers

From Sasasu
Subject Re: XTS cipher mode for cluster file encryption
Date
Msg-id d687d26c-170d-33cc-e615-98532b7d6eec@sasa.su
Whole thread Raw
In response to Re: XTS cipher mode for cluster file encryption  (Yura Sokolov <y.sokolov@postgrespro.ru>)
List pgsql-hackers
On 2021/10/26 17:33, Yura Sokolov wrote:
> Yes, AES with AES-NI is fastest. But not so much.
> 
> And, AES-CTR could be easily used instead of ChaCha12 in Adiantum.
> Adiantum uses ChaCha12 as a stream cipher, and any other stream cipher will
> be ok as well with minor modifications to algorithm.

not so much ~= half speed.

I prefer to use AES on all devices because AES is faster and more power 
efficient. using chacha only on low-end arm devices running complex 
program which most people do not have this device.

I reserve my opinion on this point, but I agree with you on the rest.
And I also agree and think it should add more algorithms. The current 
implementation does not have any reserved fields, which makes any 
upgrade like adding a new algorithm unfeasible.

On 2021/10/26 17:33, Yura Sokolov wrote:
 > That is argument. But, again, openssl could be used for primitives:
 > AES + AES-CTR + Poly/GCM. And Adiantum like construction could be
 > composed from them quite easily.

implement Adiantum is a small problem (which doesn't look good, lack 
security audits). the real problem is there are too many code path can 
trigger disk IO.
TDE need modify them. each code path has different behavior (align or 
unaligned, once or more than once). and front-end tools even not use VF 
layer, they use pread with offset. TDE need fix them all. at the same 
time, keep the patch small enough.

I still think there need a unified IO API, not only modify 
BufFileDumpBuffer() and BufFileLoadBuffer(). the front-end tools also 
use this API will be great. with that API, TDE can focus on block IO. 
then give out a small patch.

Other works can also benefit from this API, like PostgreSQL with AIO, 
PostgreSQL on S3 (BLKSZ=4M), PostgreSQL on PMEM(no FS) and many.

Attachment

pgsql-hackers by date:

Previous
From: Scott Mead
Date:
Subject: Re: [BUG] Autovacuum not dynamically decreasing cost_limit and cost_delay
Next
From: Fujii Masao
Date:
Subject: Re: Improve the HINT message of the ALTER command for postgres_fdw