Most Macs have a Secure Empty Trash feature. It will overwrite deleted data seven times. Do you want a program that goes five times further to completely destroy your data? Try Permanent Eraser.
This program overwrites deleted data 35 times to completely destroy it from your hard drive. You’ll feel much more secure knowing that your data is safe from any tradition recovery methods.
In addition to going nuclear to the file contents, it also scrambles file names and internal data like resource forks. Its method of erasing exceeds even military standards!
Permanent Eraser can also wipe CDs and DVDs.