LUKS-Encrypted File Systems NixOS supports file systems that are encrypted using LUKS (Linux Unified Key Setup). For example, here is how you create an encrypted Ext4 file system on the device /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d: $ cryptsetup luksFormat /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d 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: *** $ cryptsetup luksOpen /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d crypted Enter passphrase for /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d: *** $ mkfs.ext4 /dev/mapper/crypted To ensure that this file system is automatically mounted at boot time as /, add the following to configuration.nix: boot.initrd.luks.devices.crypted.device = "/dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d"; fileSystems."/".device = "/dev/mapper/crypted";