This question already has an answer here:

I installed Ubuntu 16.04 LTS and chose to do full disk encryption as well as home dir encryption.

At startup, I'm asked Please unlock disk sda3_crypt and I have to manually enter the disk decryption password.

I there a way to auto-mount this, i.e. by specifying the password in the boot script somewhere? (not sure about the right terminology for this) I understand this would nullify any security.

Also, is it possible to retrieve the password from a remote URL, and use that to unlock the disk and continue booting automatically?

Note that I don't want to fully disable disk encryption. I wish to keep the option to re-enable it in the future. Furthermore the retrieve password remotely option (if that's possible) would allow for other possibilities, such as enabling/disabling it remotely, or preventing someone can steal the disk or machine and access it from somewhere else.

marked as duplicate by Byte Commander, Eric Carvalho, Fabby, Elder Geek, ravery Nov 27 '17 at 4:44

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • 2
    The linked question above contains an answer suggesting exactly what you seem to want, running a tiny script that contains the plain text password and supplies it at boot automatically. Security-wise it's like disabling the encryption completely, but it saves you the time to reinstall or migrate your system to an unencrypted drive. – Byte Commander Nov 24 '17 at 14:53
  • @user535733 No, I wish to keep the possibility to re-enable full disk encryption in the future. Also, if I can somehow modify the script to retrieve the password from a remote URL (instead of including the password explicitly) I can essentially enable or disable the auto-decryption remotely. Or I could even make this remote URL work only for my fixed IP, so if the machine or disk gets stolen, someone can't access the data. – RocketNuts Nov 24 '17 at 15:47
  • Well I thought that's why I'd explicitly ask to "auto decrypt on startup" and not just "disable". But I've added an extra alinea about this. – RocketNuts Nov 24 '17 at 16:23
  • @ByteCommander Thanks, that looked promising. However I tried the approach from the comments that was specifically for 16.04.3 (which I also have) and upon rebooting I now get some kind of kernel panic error dump, and it stops completely (no interaction or option to do anything). Also tried booting in recovery mode, same. Did I just destroy my installation? – RocketNuts Nov 24 '17 at 16:49
  • What exactly did you do? Please give as much information as possible, like a screenshot from the kernel panic and what files you edited and their current content etc. Either edit your current question to include everything and describe the new situation, or even better, post a new follow-up question with a link back to this here. I can then have a look if you notify me with another comment. – Byte Commander Nov 24 '17 at 18:13