State of Argon2 support

[Nikolaos Chatzikonstantinou]

Hello list,

I was wondering what the state of Argon2 support is. From some
searches online I found patches by Patrick Steinhardt that
experimentally add support for it.

I skimmed through the discussions on this list to understand what some
of the issues are:

1. Argon2 requires a lot of memory. How to allocate without breaking
backward-compat?
<https://lists.gnu.org/archive/html/grub-devel/2020-03/msg00180.html>
2. libgcrypt does not have support for Argon2. Possible solution is to
use the reference implementation, licensed under CC0. This is bringing
up issues (that I don't fully understand), would be preferable if the
authors released under GPLv3. Has there been a follow-up on this?
<https://lists.gnu.org/archive/html/grub-devel/2020-03/msg00170.html>

I don't know if there are more issues. I would appreciate some clarity
on this. If I can help in any way please let me know. Even if you'd
just like me to read the mailing lists and patches and describe a good
summary of the state of the issue, I can do it.

The interest in getting this done comes from the Guix System project
https://guix.gnu.org/>. In this distribution, the kernel lies under
/gnu/store and the usual (for me?) plain-boot encrypted-rest setup
cannot work unless using PBKDF.

Regards,
Nikolaos Chatzikonstantinou