WIPING THE KEYBLOCK WITH SCRAMDICER

When it comes time to discard an old container, wiping the keyblock with SCD is a convenient alternative to running a filewiper against the entire container...an extra excercise of caution, surely, but hardly imprudent.

In SCD's normal operation, when it splits off the keyblock, its default action is to overwrite the keyblock just once...trusting that the equipment to burrow beneath one layer of overwrites will be out of reach of any adversary you're likely to confront. After all, there just aren't that many Usama bin Ladens, and most of you are not likely to attract as much attention to yourselves as do such hard-core life-forms.

But...if the idea of "more is better" seems appealing, here is how to do a 35-pass overwrite of the keyblocks in your SD, DC, or E4M containers using SCD's "Mask" function.

As a happy plus...if you do this to one of your working containers, one for which you already have extracted and saved a good copy of its keyblock, this procedure affords even more security for your container; for the keyblock will have been irretreivably overwritten to Gutmann levels with this second step; but is easily restored with SCD's "m" command and your saved keyblock.

HOW TO DO IT

For this purpose, the "X" command (Mask) which SCD uses to xor the keyblock with data from a separate key-file will be the most convenient; it has to used from a *.bat file, to accomodate the multiple instructions.

The trick here is to repeat the "Mask" operation on the container 35 times, using 35 different files as the source of xor'd data. For this example we'll use a number of combinations of various file-types to work this.(They must all be a little bigger than the size of your keyblocks)

You only have to prepare this *.bat file once, and then use "search and replace" to change the *.svl names if you need to get rid of another container in the future.

Place SCD.exe into the same dir as the target container; and use a "Copy Path" utility to generate the path to the files you'll be using for this. (or do it by hand...duh!) I'm assuming you use Windows Explorer for your file manager. Any file in the Windows dir will satisfy our requirements for a keyfile, btw.

Copy or type this line into a text editor, like Edxor or Notepad:

scd x data.svl *.* 0x2600

Where "data.svl" is the name of your target container...
Where "*.*" represents the path to the keyfile...
Where "0x2600" is the size (in hex) of your containers keyblock...

Copy the string to the clipboard and paste it back in four (4) more times:

scd x data.svl *.* 0x2600
scd x data.svl *.* 0x2600
scd x data.svl *.* 0x2600
scd x data.svl *.* 0x2600
scd x data.svl *.* 0x2600

Copy the whole group and paste it back six (6) more times till you have all 35 lines on the page. (7x5=35...heh)

Right-click on the first keyfile in Explorer and choose "Copy Path"; high-lite the "*.*" in the first line in the editor and paste the path-name right over it.

Repeat this with the next 34 lines, and use the paths to 34 more files (they have to be bigger than your keyblock)

The result may look like this (for the first few lines in this example)

scd x data.svl D:\new_images\bro2.tga 0x2600
scd x data.svl D:\new_images\opr00H4C.avi 0x2600
scd x data.svl C:\Temp\man.doc 0x2600
scd x data.svl C:\WINDOWS\StupidCupid.scr 0x2600
scd x data.svl C:\WINDOWS\SCANREGW.EXE 0x2600
scd x data.svl C:\WINDOWS\LOGOS.SYS 0x2600
scd x data.svl C:\zipz\misc3.jpg 0x2600
28 more like these :)

Save this new text file with the *.bat extension ("trash.bat"), and place it in whatever dir that you keep SCD.exe in. If you add the entire path to the target *.svl in each line of the *.bat, you can run "trash.bat" from the same floppy or small SD container that holds SCD.

scd x D:\data.svl C:\WINDOWS\StupidCupid.scr 0x2600
scd x D:\data.svl C:\WINDOWS\SCANREGW.EXE 0x2600
scd x D:\data.svl C:\WINDOWS\LOGOS.SYS 0x2600

Run the bat right after you split off the keyblock for the last time; and when you're done, the old extracted keyblock is the only thing that needs to be erased...the container will be nuetered as far as an attacker would be concerned, and you can simply delete to dispose of it.

Save this handy new bat-file where ever you hide SCD...but you may want to change the extension from "*.bat" to ".txt" first; to prevent any accidents.