Deleting Data/Wiping


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Section ofDeleting Data
  • Last modified: 6 August 2013 17:18:21

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Discuss the realities of digital data storage and subsequent problems of normal data deletion. Move on to data recovery and coming out of that explain how 'free space' on a computer could still hold many old files. Briefly introduce the process of wiping data and the methods that exist to do so. Explain the purpose of multiple passes and the relevant time requirements. In summary, or at the end of the session describe the difference between Ccleaner and Eraser, the main of which being that Ccleaner's original function was to wipe temporary files - although now it also does standard file wiping and free space.

Trainer's notes: introduce and stick to a new naming convention that distinguishes between deleting and permanent deleting (wiping or erasing).


Standard installation. Successful installation will display the Eraser icon in the Windows System Tray after reboot and will enable Eraser options on the Windows Explorer right-click menu.

Trainer's notes: Although available in portable version, it is not recommended to use Eraser from a USB stick. You should also choose between the installation of Eraser 5.8 and 6.X The latter version does not have the 'Secure Move' function. It is not proven whether the latter version is more effective in wiping data, free space.


Set the wiping preferences, explaining the reasons for the number of passes. Talk about file wiping and free space. In Eraser, explain the 'swap' file option, password protection and scheduler.

Wiping Data

  1. Perform a file wipe using the Explorer extension.
  2. Perform a folder wipe using the Explorer extension.
  3. Perform a file & folder wipe using the Eraser interface.
  4. Perform a secure file move (from the computer to the USB memory stick) using the Eraser Explorer extension.

Trainer's notes: Prepare a set of files and folders for erasing in advance. Optionally, ask your participants to create the files and folders themselves. Do NOT wipe 'real' user documents.

Wiping free space

  1. Ask the participants to 'Wipe Free Space' task from the USB memory stick
  2. (Optional) Perform a free space wipe of the C: drive

Trainer's notes: Make sure that only one pass is chosen for the free space wipe session, otherwise it will take too long to complete. You could schedule a coffee break to occur during the wiping process. It may be interesting to try undelete software at the end of this process to ensure participant's of its effectiveness.

Additional software descriptions

The patterns used for overwriting are based on Peter Gutmann's paper Secure Deletion of Data from Magnetic and Solid-State Memory (the one who recommends the 35 pass method for secure deletion) and they are selected to effectively remove magnetic remnants from the hard drive.

Other methods include overwriting with pseudorandom data. You can also define your own overwriting methods.