If a file contains any information that is subject to PCI (credit card numbers - whether encrypted or not) or you have other sensitive patron information or a database, then you should erase it securely per PCI-DSS standard 9.8.2. This is because any files that are erased normally can sometimes be retrieved if the file is not over-written and securely erased. |
Securely erasing a file is quite easy to do on OSX. Simply:
Windows does not offer a built in feature to securely empty the trash so you will need to install a small utility to do this. It has some benefits in that files put in trash can be erased on a periodic basis so the process becomes automatic.
If you have not done so, you will need to obtain the free utility called 'Eraser' and install it as follows:
You will see the 'Erase Schedule' window again, with a task in it.