Changing file mounted as loop device

From: Anthony Starovoytov (
Date: 05/26/04

  • Next message: cherico: "md5sum some ISOs"
    Date: 26 May 2004 03:15:30 -0700

    I have the following problem: due to the security reasons I'd like to
    make a partition unreadable for other persons even if they will switch
    off the power, take my hard disk and install on their workplace. I did
    not want to use crypto apis cause they could be slow. My idea was to
    create a file, bind it to the loop device, mount and then change first
    X bytes with the random data. And replace them with the correct ones
    before mounting and umounting and then change back to random.

    I got the stange (but probably correct) behaviour: if I change the
    file after mounting, all the changes could be discarded under unknown
    rules - they could be new random now and when I view the file in 1
    second, it contains the old correct data.

    So it stores somewhere the correct beginning?
    My question is: how I can reach my goal, probably using other ways.
    But it would be also very interesting why it behaves so and where I
    can read what actually is done when mounting files using loop devices
    and why it restores them.


  • Next message: cherico: "md5sum some ISOs"