How to Automatically Mount LUKS

This tutorial assumes you sort of know what you’re doing and how to identify the device you wish to encrypt. For simplicity sake we’ll assume in this tutorial you’ve encrypted /dev/sdb1 using the handle sdb1_enc and mounting to /mnt/enc.

Add a random key

cryptsetup luksAddKey /dev/sdb1 RandomStringNeedsToBeLong

Better to create and use a long random string.

pwgen -s 64 1 > keyfile.asc
cryptsetup luksAddKey sdb1_enc ./keyfile.asc

Use the random key

Place the file keyfile.asc and use it to open a LUKS volume.

cat /root/keyfile.asc | cryptsetup luksOpen /dev/sdb1 sdb1_enc

Or from online.

curl -s https://domain.tld/keyfile.asc | cryptsetup luksOpen /dev/sdb1 sdb1_enc

Add to /etc/crypttab

sdb1_file /root/sdb1 /root/keyfile.asc luks

Add to /etc/fstab

/dev/mapper/sdb1_file /mnt/enc ext4 defaults 0 2