Hi everyone, I found the great question on booting encrypted drives, and since I’m somewhat paranoid I’d like to ask a follow-up:

When the key to decrypt the drive is input into the system, I’m assuming it stays in the RAM till the time the computer shuts downs. We know that one could, in theory, get a dump of the contents of the RAM in such a state, if done correctly. How would you deal with this problem? Is there some way to insert the USB, decrypt the drive, and then remove the USB and all traces of the key from the system?

Thanks!

Edit: link to the question I referenced: https://feddit.de/post/6735667

  • aard@kyu.deEnglish
    4·
    11 months ago

    This level of paranoia isn’t really compatible with modern hardware, and requires a lot of effort.

    You’re pretty much limited to stuff that has open firmware available, and even then you have to hope there are no bugs or backdoors in the hardware.

    For the intel world almost everything with open firmware is pretty old - some nowadays unsupported, which means no longer microcode updates. And those microcode updates also are a problem - you can’t mitigate everything in kernel space, so usually you’d want them, but they’d also be an attack vector against you.

    And even if you manage to trust the computer itself there are a lot of attack vectors surrounding it. Do you have anything capable of recording audio in the same room as your computer? If yes, not a good idea - it has been proven possible to extract passwords from audio recordings of a keyboard. Does the room have windows? That counts as an audio recording device.

    If you got rid of that, do you have some other hardware with sensors? There’s a high chance that a device placed on your desk containing an accelerometer would also be capable of extracting your password.