No data security system would be complete without a way to destroy the original versions of a file after they are encrypted. Burn provides exactly that function. It is a drag-and-drop application under system 7. Files and folders dragged onto the Burn icon will be overwritten a user selected number of times with a user selected pattern, then renamed, then deleted. Both data and resource forks are deleted.
A variety of options allow you to configure the application to exactly the ease of use and security you need. No matter what options you select, your trash will be far more secure than if you used Apple's built in trash capabilities.
This application is not a replacement for the trash can. You should continue to drag unimportant documents and applications to the trash can. When you drag a file to the Burn icon it will be irretrievably deleted.
To destroy a file or folder simply drag the desired item to the Burn icon and release the mouse button. The item will be overwritten and deleted. You can also destroy a file or folder by double clicking on the Burn application and then selecting "Delete..." from the file menu. You will be prompted to select an item for destruction.
Warning: Burn does not handle alias's the same way the trash icon in the Macintosh Finder does. If you drag an alias record to Burn (or open an alias from within the application) the ORIGINAL file will be destroyed, not the alias.
Burn allows you to erase the contents of the free sectors on your disks. This option is useful if you accidentally erased a sensitive file using the regular trash can, or if a file was deleted within an application. It is very safe because what it does is create a temporary file the size of the free space on your disk, and then burns that file. Thus there is no risk of Burn wandering off into parts of your hard disk that it should not venture (well almost no risk, see the next paragraph).
Warning: Disks with a damaged directory can be further damaged if you Burn the free space. Be certain your disks are healthy by running a utility program such as Apple's Disk First Aid before using Burn's Erase Free Space command.
To use this feature select "Erase Free Space..." from the file menu. It will prompt you to select a volume to clean. A status dialog will show the progress of the cleaning.
For maximum security you should periodically select this option.
The "Preferences..." option under the file menu of Burn allows you to customize the behavior of Burn to suit how you use it. Below each option is described in detail.
Confirm Deletes
This option, if selected, will cause Burn to ask you to confirm the destruction of each file. It provides a "Delete All" button in the dialog box to bypass further confirmations if you are confident you know what you are doing.
Display Status
This option if selected will display a dialog box during destruction, showing the progress of the destruction. Burn will quickly destroy normal sized files, but you might want to select this option if you frequently burn large documents.
Erase Patterns
This pop-up menu lets you select the erase pattern Burn should use when overwriting files. If you are using only a single pass select all zeros or all ones for quick but good security. For maximum security you should probably select Random (and multiple passes).
Erase Passes
This pop-up menu lets you specify the number of erase passes Burn should make over the file while destroying it. For maximum security, select at least three. Anything over a single pass is serious overkill though unless you expect your hard disk to be in the NSA's hands anytime soon.
The following screen shot from the Script Editor demonstrates how to script Burn:
Burn continues to respond to the Open Document apple event and is fully backwards compatible with any Burn 2.2 script you may have.
There are a few things you need to be aware of using this or any file destruction utility.
Burn does its best to destroy filenames along with files, however the Macintosh Operating System, probably for performance reasons, makes it difficult to destroy filenames with 100% certainty. This version of Burn seems to destroy the filename ninety percent of the time but it is not perfect. Do not assume Burn can reliably erase the name of a burned file. Other disk erase applications, including Norton Wipe Info and FlameFile have the same problem.
You should be concerned if you have a file that significantly grows or shrinks in size (maybe a database file for instance.) There is no way for an application like Burn to know that some disk blocks used to be allocated to the file if it shrinks. Use the Erase Disk Free Space to minimize this problem.
Recently deleted files are not always immediatly marked as free by the Macintosh Operating System, probably for performance reasons. This means that the Erase Free Space command may not destroy data from recently deleted files. Of course files erased with Burn are destroyed 100% of the time. Use a utility such as Norton Unerase to verify the files are truely destroyed or use Burn to erase free space a couple of times over a few days.
If you are an Engineer with intimate knowledge of the Mac File Manager please contact me if you can be of assistance in the above problems. I'm looking for someone who has written File Manager code or equivalent (such as Norton Utilities).
Something caused Burn to be prematurely terminated. You will find a file in the root directory of the disk being cleaned equal in size to the missing disk space. This file should be deleted using the normal trash can and then repeat the Erase Free Space operation. The file's name starts with the characters "MwBu" and after that is a long series of numbers.
Burn temporarily grabs all available free space on a volume while its erasing it. With Burn in the background during such an operation you can't do things that require additional disk space to be allocated. As soon as Burn completes its operation you will be able to create new files.
You need to rebuild your desktop (this is a good idea to do regularly anyway). Reboot your computer and hold down the command and option keys until you get a message asking if you want to rebuild the desktop. Click okay.
I provide full support for Burn. Don't hesitate to send mail with questions, bug reports or suggestions. I want this program to be the best there is, and I want you to be a satisfied user.
I am not responsible for any loss or damage due to any failure of this program regardless of the cause.
Burn, a product of Next Wave Software is © 1993-1998 by Michael Watson and Paul Jensen. This program is not in the public domain. Next Wave Software, Inc. reserves all rights to this program.
You are free to distribute this program to other users provided this documentation is enclosed. The program can not be offered for sale without my permission. Enclosure as part of a user group shareware collection is allowed so long as the collection is sold only to recover distribution costs.
Any party desiring to include this program as part of a shareware collection that is sold on a for profit basis must receive written permission from the author.