Now you have a password-protected .dmg file which you can access with only a double click. The image will be mounted in Finder, and after that, you will just have to write down your password to ...

Some applications have password protection features built in, while in other cases you'll need to lock up your files using a different method.

Password protecting a file It is possible to add password protection to many file types, eg word processing documents, spreadsheets and presentations.