Mac OS X offers you a smart built-in solution to secure your files and folders. It is possible to create an encrypted disk image, it is like a regular disk image but requieres a password to become mounted. How this works, I'd like to show you in the following steps:
- Open Disk Utility (press ⌘ + SPACE and type disk utility).
- File > New > Blank Disk Image.
- Type a name in the Save As field. This name will be used for the disk image.
- Choose a preferred location to save the *.dmg file.
- Select a size for the disk image.
- Choose as volume format the default Mac OS X Extended (Journaled)
- Use "sparse disk image" for a disk image that only uses as much space as it needs, rather than a set amount of space.
- Choose 128-bit AES encryption (or 256-bit AES in Mac OS X v10.5 or later, but slower). I would suggest 128-bit AES encryption.
- Click on "Create" button.
- Enter a strong password and don't forget to deselect "Remember password (add to keychain)" if you don't want it saved. Because if you do, your created disk image is less secure.
