Cipher Preferences Ignored for Kyber keys?

[scuffbox]

On Sunday, 26 July 2026 at 15:35, Damien Goutte-Gattat wrote:
> On Sun Jul 26, 2026 at 12:07 AM BST, scuffbox via Gnupg-users wrote:
> > On upgrading to 2.5.x (2.5.20 and 2.5.21) recently to test Kyber keys, 
> > I have noticed that any preferences relating to cipher choice are 
> > being ignored.
> >
> > AES256 appears to be used for encryption to Kyber subkeys regardless 
> > of the contents of the public key's cipher preferences and the local 
> > config's personal-cipher-preferences.
> 
> Indeed. This is a deliberate behaviour, see the discussion on issue 
> https://dev.gnupg.org/T7472.
> 
> When all the keys we are encrypting to are Kyber keys, then AES-256 is 
> forcefully used regardless of the preferences.

Thanks for the reply and link to discussion (I did have a look before posting,
but obviously not hard enough).

I had wondered if the issue may have something to do with expected key size,
which appears to be the case. It would still be nice for preferences to be
honored where ciphers use a suitable key size though. GnuPG supports at least
two other ciphers with 256bit keys, TWOFISH and CAMELLIA256, which may be
used instead of AES256 if all recipients support/prefer them.

Perhaps the current approach could be re-visited at some point to cater for
suitable recipient/personal preferences?

--
Scuff