<section xmlns="http://docbook.org/ns/docbook"
         xmlns:xlink="http://www.w3.org/1999/xlink"
         xmlns:xi="http://www.w3.org/2001/XInclude"
         version="5.0"
         xml:id="sec-luks-file-systems">
 <title>LUKS-Encrypted File Systems</title>

 <para>
  NixOS supports file systems that are encrypted using
  <emphasis>LUKS</emphasis> (Linux Unified Key Setup). For example, here is how
  you create an encrypted Ext4 file system on the device
  <filename>/dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d</filename>:
<screen>
<prompt># </prompt>cryptsetup luksFormat <replaceable>/dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d</replaceable>

WARNING!
========
This will overwrite data on /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d irrevocably.

Are you sure? (Type uppercase yes): YES
Enter LUKS passphrase: ***
Verify passphrase: ***

<prompt># </prompt>cryptsetup luksOpen <replaceable>/dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d</replaceable> <replaceable>crypted</replaceable>
Enter passphrase for /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d: ***

<prompt># </prompt>mkfs.ext4 /dev/mapper/<replaceable>crypted</replaceable>
</screen>
  The LUKS volume should be automatically picked up by
  <command>nixos-generate-config</command>, but you might want to verify that your
  <filename>hardware-configuration.nix</filename> looks correct.

  To manually ensure that the system is automatically mounted at boot time as
  <filename>/</filename>, add the following to
  <filename>configuration.nix</filename>:
<programlisting>
<link linkend="opt-boot.initrd.luks.devices._name_.device">boot.initrd.luks.devices.crypted.device</link> = "<replaceable>/dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d</replaceable>";
<xref linkend="opt-fileSystems"/>."/".device = "/dev/mapper/<replaceable>crypted</replaceable>";
</programlisting>
  Should grub be used as bootloader, and <filename>/boot</filename> is located
  on an encrypted partition, it is necessary to add the following grub option:
<programlisting><xref linkend="opt-boot.loader.grub.enableCryptodisk"/> = true;</programlisting>
 </para>
  <section xml:id="sec-luks-file-systems-fido2">
  <title>FIDO2</title>

  <para>
   NixOS also supports unlocking your LUKS-Encrypted file system using a FIDO2 compatible token. In the following example, we will create a new FIDO2 credential
   and add it as a new key to our existing device <filename>/dev/sda2</filename>:

   <screen>
<prompt># </prompt>export FIDO2_LABEL="<replaceable>/dev/sda2</replaceable> @ $HOSTNAME"
<prompt># </prompt>fido2luks credential "$FIDO2_LABEL"
f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7

<prompt># </prompt>fido2luks -i add-key <replaceable>/dev/sda2</replaceable> <replaceable>f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7</replaceable>
Password:
Password (again):
Old password:
Old password (again):
Added to key to device /dev/sda2, slot: 2
</screen>

  To ensure that this file system is decrypted using the FIDO2 compatible key, add the following to <filename>configuration.nix</filename>:
<programlisting>
<link linkend="opt-boot.initrd.luks.fido2Support">boot.initrd.luks.fido2Support</link> = true;
<link linkend="opt-boot.initrd.luks.devices._name_.fido2.credential">boot.initrd.luks.devices."<replaceable>/dev/sda2</replaceable>".fido2.credential</link> = "<replaceable>f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7</replaceable>";
</programlisting>

  You can also use the FIDO2 passwordless setup, but for security reasons, you might want to enable it only when your device is PIN protected, such as <link xlink:href="https://trezor.io/">Trezor</link>.

<programlisting>
<link linkend="opt-boot.initrd.luks.devices._name_.fido2.passwordLess">boot.initrd.luks.devices."<replaceable>/dev/sda2</replaceable>".fido2.passwordLess</link> = true;
</programlisting>
  </para>
 </section>

</section>
