Safe Storage of Your Vital Information
by Harry Lienke
There is much information the experts say you should keep in a convenient, but secure, place. The information includes Social Security numbers, credit card numbers, checking and savings account numbers, household inventory, and driver’s license numbers; this is just a sampling of the data about your life that should be collected, saved, and protected.
This data can be stored in one or more files on your Macintosh computer, but how secure is your Mac? Typically, folks tend to let the Mac OS log on to their account automatically when they turn the power on or restart their Mac. This leaves all your files vulnerable to anyone who wanders by your computer; in addition, it makes it easy for a thief to access all those files after pilfering your computer. Even if you set up your account to require a password to log on, a thief can either use an installation disk to reset your passwords or use another computer to access data on your hard drive. Without some additional protection, your data is vulnerable while it is on your Mac.
One possibility to safeguard your valuable data is to use one of the many shareware applications designed to store that data in an encrypted database. This is a viable alternative, but it requires that you pay a shareware fee; why use a shareware application when there are good, free alternatives?
One possibility with no cost is the FileVault capability of Mac OS X. You can protect all the data in your Home folder with FileVault; one disadvantage of using FileVault is that it protects everything in your Home folder, possibly including all your photos and music. You may find that you need a hard disk to back up your data for storage off-premises. An easier solution is to store all your important data in an encrypted form that allows you to back up that data on CDs or DVDs you can store in a safe deposit box, in your desk or locker at work, or on a shelf at Aunt Polly’s house. You can use Apple’s Disk Utility to create this vault for your data.
Let’s Create a Secure Storage Area
In the following paragraphs information contained in square brackets [like this] represents menu items to be selected, information to be entered, and/or actions to be taken. Open the Disk Utility program located within the Utilities folder that lies within the Applications folder on your hard drive. Open the Disk Utility’s File menu and create a disk image file [File-New-Blank Disk Image] (see Figure 1) about the same size as a CD-ROM [Size = 660 MB] with encryption enabled [Encryption = AES-128] and a read/write disk image format [Format: read/write disk image]; also specify you want the disk image created on your [Desktop], not, for example, in the Documents folder (see Figure 2).
Figure 1. Creating the Disk Image
Figure 2. Disk Image Attributes Figure 3. Password Entry
After you provide a name for your new disk image file and volume [Save As: MyData, for example] and click on the Create button, Disk Utility asks for a password (see Figure 3). Provide a very strong password: at least 10 characters long using numbers, lower and upper case letters, and special characters. Do not use easily available information about you and your family. You will not be able to retrieve your data if you forget the password; the password should be memorable for you but, to provide good protection, very difficult for others to guess. If you would like the Mac OS X Password Assistant to help select a password, click on the button that is located to the far right of the “Password:” prompt (it has a key on it). The Password Assistant generates a variety of passwords but even the “Memorable” passwords are probably going to be less memorable than a password you generate yourself.
Do not allow the password to be Remembered or Added into the Keychain [click on the Check Mark if one is present to delete it]; if you allow the password to be Remembered, you have weakened your security to the level of any password you use to sign on to your computer. If you write your password down, keep the piece of paper well away from the data you are trying to protect — in a safe deposit box or a relative's house, for example, but not located near your Mac or in the same place you are storing your back-up data. After you enter the password and click on the OK button, Disk Utility creates a desktop disk image file with the name you specified and a suffix of “.dmg” (MyData.dmg, for example) with the protected volume residing within the disk image. The disk image file and the protected volume are shown on the far left side of the Disk Utility window (see Figure 4).
Figure 4. Files in Disk Utility Figure 5. Disk Image and Protected Volume
Quit the Disk Utility and you can see the disk image and volume icons on your desktop (see Figure 5). Since the disk image file is open and the protected volume is available, you may write and/or read files on the protected volume like you do with a standard hard drive volume.
Whenever the disk image is closed and you need to read from or write to the protected volume, double-click on the disk image and you are asked for the password; after you have entered the password, a volume with the name you specified (MyData, for example) appears on your desktop. As mentioned above, use the volume like a standard hard disk volume. After you have finished reading and/or writing, make sure you eject the volume (control-click on its icon and select Eject [Eject “MyData”, for example] from the menu that appears) so no one can access it without the password; if you leave the volume sitting open on the desktop, anyone can access its data and you have defeated the purpose for creating an encrypted disk image.
To back up the data to a CD-ROM, close the protected volume (if it is open) by ejecting it so no icon with the volume’s name is showing on the desktop. Insert a blank CD in the CD-ROM drive and let the Finder handle the processing of the blank disk [Action: Open Finder and click the OK button]. Give the blank CD an appropriate name by clicking twice (two separate clicks, not a double-click) on the blank CD’s name, “Untitled CD”, and entering a new name (for example, Backup20080410). Drag the .dmg file to the icon of the blank CD and then click on the icon of the blank disk to select it. Tell the Finder to burn the CD [File-Burn Disc...]. This process makes a back-up disk which is also encrypted.
To access the data on the back-up CD, insert the CD into the CD-ROM drive and, after the CD’s icon appears, double-click on it. A window showing the disk image file (MyData.dmg, for example) appears; double-click on the disk image file to begin opening it. Mac OS X asks for the password of the disk image file; enter the password to finish opening the protected volume (MyData, for example). You can now access any of the data on the volume. Your data is secure on the back-up disk because your password is required to open the disk image.
I have a set of CD-RW disks I use for back-ups on a rotating basis. Once a month or so I erase the data on the oldest disk and re-write it with the latest data. I keep a couple of disks at home and the remaining back-ups off-premises so my data is conveniently located but protected against catastrophes.