Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

To be specific, I want it to be impossible to boot up my linux computer without a certain sdhc card inserted. And I don't want the bios to boot from the sdhc card. Also, if the sdhc card is removed when the computer is on, I want it to do a full secure wipe of the main hard drive.. I have no idea where to start on this and I couldn't find anything on google except booting with a full linux image on the sdhc card, which I don't want. So the sdhc card would be the /boot partition. But how to only boot from my sdhc so that if someone else tries to use their own sdhc card to boot, it will deny access....

share|improve this question

migrated from Jul 5 '13 at 3:37

This question came from our site for system and network administrators.

Look into LUKS encryption methods, and the ability to store the key on your SD card. – Soviero Jul 5 '13 at 3:45
I would think that LUKS would only access the key at boot, and so doesn't meet the second criteria of wiping. You could script that, but then you'd want it pretty robust. In the event the usb controller glitches, would you be happy for the disk to be wiped? – Paul Jul 5 '13 at 4:32

Just a few thoughts.

As mentioned by Kevin Soviero I would look into LUKS for the encryption and storing the keyfile on a external device. You can find information for instance at

For the second part I would look into udev and create a rule that would call a script to wipe things when the card is removed.

You can test your setting by actually removing the SD card. Don't forget to make an exact copy of your hard disk beforehand.

share|improve this answer

You must log in to answer this question.