MacAppStuff Blank for Mac

From MacAppStuff:

MacAppStuff Blank erases unused space on hard disks, USB flash drives etc, to prevent the recovery of deleted files. Any data which still resides in that unused space, albeit marked 'free', can be properly and securely deleted by overwriting it. As you may know, simply deleting a file does not actually delete the content of the file. Instead, the space that file occupied on the disk is simply marked as being 'free', and may exist for a long time until another file is allocated that space (or part of it).

Simply check the drive(s) you want to work on, the number of passes you want to perform and click the "Start" button (the trial version is restricted to one pass only).

When wiping begins, you are shown the following information:

• The name of the volume whose free space is currently being wiped.
• The value being used to overwrite the data (see Preferences).
• The current block (blocks are files the application writes to your volume, they are temporary and deleted after wiping has completed successfully).
• The current pass of the block.
• The number of remaining blocks yet to be made.
• The total progress.

The time it takes to wipe a volume depends on the size of the volume, the speed of your Mac (and amount of RAM), and how many passes you specify. Obviously, 8 passes will take eight times longer than 1 pass.