Re: Btrfs Fscrypt Design Document

[Vadim Akimov <lvd.mhm@xxxxxxxxx>]

On Mon, 25 Oct 2021 at 22:59, Eric Biggers <ebiggers@xxxxxxxxxx> wrote:

> However,
> given that btrfs is a copy-on-write filesystem and thus can support per-block
> metadata, a natural question is why not support an authenticated mode such as
> AES-GCM, with a nonce and authentication tag stored per block?  Have you thought
> about this?

Can't the existing checksum fields be just reused to keep HMACs? This
way even the unencrypted metadata could be authenticated.