➥ Encrypting a usb drive with cryptsetup Luks

# cryptsetup luksFormat /dev/sdX
# cryptsetup open /dev/sdX encrypted
# mkfs.ext4 /dev/mapper/encrypted
# cryptsetup luksOpen /dev/sdX encrypted
# mkdir /place/to/mount
# mount -t ext4 /dev/mapper/encrypted /place/to/mount
# umount /place/to/mount
# cryptsetup close encrypted