Encrypting Only Certain Files

Encrypting your whole Home folder might not always be the most convenient way of doing things.  It could also bring slowdowns on older Macs as on the fly encryption can be demanding for the system.  Another possibility is that you might want to have certain files encrypted and passworded even when your computer is running and your account logged in.  The solution to that is an encrypted and passworded Disk Image.  Disk Images can easily be created in Disk Utility.  Disk Utility is located in the “Utilities” folder that is in the “Applications” folder. 

1. Once Disk Utility is open, click on “New Image” in the upper left.

2. This window will pop up:

Encrypting Virtual Memory

Even if you enable the encryption on your disk so that all files stored are safe, a hacker could theoretically hack in to your computer and access the unencrypted content of your virtual memory.  The only way of making sure that some information is really gone or encrypted would then be to restart your computer very often.  That is not very convenient.  To avoid this, there is an option called “Use secure virtual memory”.  This will basically encrypt all the data that is temporarily stored on your hard drive.  To enable this great security feature:

1. Open System Preferences.

2. Choose “Security”.

3. Check “Use secure virtual memory”.

3. You can first name the disk image and choose where you want to save it.

4. Then you can choose the size according to the files you want to store.

5. To get the safe encrypted disk image, choose AES-128 as encryption.

6. The “Read/Write Disk Image” will allow you to easily modify, remove and add files.

7. Click on “Create”.

8. Since you selected an encrypted disk image, it will ask you for a password.  Just like encrypting with FileVault, if you forget your password, you lose all your files.

9. You are done!  The disk image is now created where your chose to save it.  When you mount it, it will ask for a password.  The password will decrypt the data and you will have a full access to your files.  When you are done, you eject the mounted disk image as though it was a DVD.  When the disk image is ejected, it is impossible to have access to your files without your password.  To mount the disk image again, just double-click on the saved file.

4. File Safeguarding

Encrypting with FileVault

FileVault is a security option included with your Operating System that adds an extra level of security to the files stored on your hard drive.  Per example, if your computer was stolen, even though you have a password set at login, anyone could retrieve your files by simply reading the content of your hard drive.  Instead of booting from that drive (which would require a password), a hacker could simply set the hard drive as a secondary drive and read the whole content.  This issue can be easily resolved with encryption.  Encrypted files won’t be as easily read without the password.  A good encryption is very hard to break, even by professionals.  So that is exactly what FileVault is about, it encrypts and decrypts the files in your Home folder on the fly.  The only disadvantage of encrypting is that if you forget your password, all the files are lost.  One of the features of FileVault is a master password, so if you forget your account password, you can use the master password to unlock your files or the files on any account on that particular computer.  To avoid losing your files because of a forgotten password, you can create this master password and write it down somewhere hidden in case something happens.  To activate FileVault on your account:

1. Go to the Apple menu and choose “System Preferences...”.

2. In the “Personal” section, choose “Security”.

3. Press “Turn On FileVault...”

You can also set the Master Password with the button just over “Turn On FileVault...”.