Our website provides a free download of Overwritten X 1.0 for Mac. Overwritten X for Mac lies within Security Tools, more precisely General.
From the developer:
Overwritten uses 'srm' to rename and overwrite files repeatedly in order to ensure they cannot be recovered, even through extensive examination.
You may want to check out more software for Mac, such as Permanent Eraser, ImageFetch or CopyMergeForOSX, which might be similar to Overwritten X.