[Image description:
Screenshot of terminal output:

~ ❯ lsblk
NAME           MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINTS
sda              8:0    1  62.5M  0 disk  
└─topLuks      254:2    0  60.5M  0 crypt 
  └─bottomLuks 254:3    0  44.5M  0 crypt

/end image description]

I had no idea!

If anyone else is curious, it’s pretty much what you would expect:

cryptsetup -y -v luksFormat /dev/sda
cryptsetup open /dev/sda topLuks
cryptsetup -y -v luksFormat /dev/mapper/topLuks
cryptsetup open /dev/mapper/topLuks bottomLuks
lsblk

Then you can make a filesystem and mount it:

mkfs.ext4 /dev/mapper/bottomLuks
mount /dev/mapper/bottomLuks ~/mnt/embeddedLuksTest

I’ve tested putting files on it and then unmounting & re-encrypting it, and the files are indeed still there upon decrypting and re-mounting.

Again, sorry if this is not news to anyone else, but I didn’t realise this was possible before, and thought it was very cool when I found it out. Sharing in case other people didn’t know and also find it cool :)

  • hperrin@lemmy.world
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    8 months ago

    It would be good if you wanted to have a system that two people need to be present to unlock. Like those nuke launch locks that need two keys.

    • Jawa@lemmy.world
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      8 months ago

      You can also just split the password for a single LUKS into two parts and give one each to the two people :D

      • flashgnash@lemm.ee
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        8 months ago

        But then you know both parts of the password and so must be killed to keep the machine secure

        • Jawa@lemmy.world
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          8 months ago

          Ideally you would never have to because you just have the two people come up with their part of the password and then initialise the LUKS partition together. Sorta like a key ceremony