Re: [RFC PATCH 4/7] crypto: remove ARC4 support from the skcipher API

[+linux-wireless, Marcel Holtmann, and Denis Kenzior]

On Thu, Jul 02, 2020 at 12:19:44PM +0200, Ard Biesheuvel wrote:

Remove the generic ecb(arc4) skcipher, which is slightly cumbersome from
a maintenance perspective, since it does not quite behave like other
skciphers do in terms of key vs IV lifetime. Since we are leaving the
library interface in place, which is used by the various WEP and TKIP
implementations we have in the tree, we can safely drop this code now
it no longer has any users.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

Last year there was a discussion where it was mentioned that iwd uses
"ecb(arc4)" via AF_ALG.  So can we really remove it yet?
See https://lkml.kernel.org/r/97BB95F6-4A4C-4984-9EAB-6069E19B4A4F@holtmann.org
Note that the code isn't in "iwd" itself but rather in "libell" which iwd
depends on: https://git.kernel.org/pub/scm/libs/ell/ell.git/

Apparently it also uses md4 and ecb(des) too.

Marcel and Denis, what's your deprecation plan for these obsolete and insecure
algorithms?

- Eric