Password Protect Files on a Mac
This technique follows similar steps to the "How to Make a DMG" article but places the emphasis on how to use a DMG as a secure, folder-like container for your personal and secret files.
This article is not designed to secure your user account! For that, Apple provides a service called FileVault.
Contents
[hide]Steps
- Create a New Folder on the Desktop. Right Click on the Desktop, then click on "New Folder". This is where you will place your secret files later.
- Open the location of the secret files on Finder.
- Drag and drop the secret files to the newly created folder on your Desktop.
- Right click the folder and select "Get Info". Note the size of its contents (in MB); this will be very important in Step number 6.
- Open "Disk Utility". A new window will open.
- The quickest way to do this is by using Spotlight.
- Alternatively, you can also go to Applications > Utilities > Disk Utility
- Click "New Image", then name the Disk Image to be created.
- Click on the "Size" category, then click "Custom..." Enter the file size in MB which you acquired from Step number 4. Then, add 5 MB to that value. Click on OK.
- 5 MB is added to make room for cache purposes.
- You cannot create a Disk Image less than 10.5 MB.
- In the "Encryption" category, select "128-bit AES encryption".
- Leave "Partitions" and "Image Format" in their default settings.
- "Partitions" should be "Single partition - Apple Partition Map"
- "Image Format" should be "read/write disk image"
- Click on "Create" to create the Disk Image. After the progress bar completes, a new window will appear where you can enter your password.
- Enter your "Password" and re-type it in the "Verify" box.
- A Password Strength indicator will tell you if your password is strong or not.
- For better results, use capital letters, numbers, and special characters.
- Uncheck the "Remember password in my keychain" option. Then, click on OK.
- This is important! If you keep this checked, then anyone can simply open your secret files because the password is saved in the computer memory.
- The purpose for this Disk Image password is that you have to enter a password every time you want to access your secret files.
- Transferring your secret files to the Disk Image. Drag and drop your secret files into the Disk Image you have just created.
- Don't forget to eject the Disk Image after you are done viewing your secret files! Finished!
Tips
- Store personal information such as bank statements, credit reports and other sensitive documents in this disk image.
- You can store your Quicken data file in this image, however, you will have to mount the disk image before you open Quicken.
Warnings
- Do not add the password to your keychain
- Make sure you choose a password that you will remember as once you have encrypted these files with that password, you will not be able to access them without it.
- DMG files are only accessible on a Mac.
- Do not write the password down or put in on the computer
