By default, even if during setup you choose an alternative layout, you’ll have to type your passphrase in US keyboard layout. As there is no GUI option to do it, we will see how to do it using terminal.
First, we will check the locale currently set on computer.
localectl
As you can see, my system is in en_US but my keyboard is fr / azerty.
Let’s modify the file /etc/vconsole.conf to reflect this at startup.
sudo nano /etc/vconsole.conf
By default, there is only the KEYMAP.
But that doesn’t work to have the correct layout at LUKS decryption.
Add the following line
LANG=fr_FR.UTF-8
It must match your keyboard layout. Here it is for french keyboard. For example, German keyboard will be de_DE.UTF-8.
You can list the locale installed on your computer with
localectl list-locales
You can now reboot and unlock your computer with your correct keyboard layout.