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Hide your files in secure disk vaults

We all have files and information stored on our computers that we would rather keep secret. This may be a note with your bank details such as account number and branch address, or your password to get into your online banking account. You may store home or work accounts information, or files that are needed for your tax return. There might be login details for the miriad of sites that seem to require logging in before you can access them, there may be subscription details for magazines you subscribe to, and so on.

Just think about it for a minute; if someone got hold of your computer, what files and information would they have access to? Wouldn't it be a good idea to secure those files in an uncrackable disk vault that only you could access? You can and you already have the software tools on your Mac.

The utility to create secure disk vaults that can be used to keep files hidden from everyone except yourself is none other than good old Disk Utility. Go to the Applications/Utilities folder and run it. Select File, New and you have a choice of two options. You can either turn an existing folder into an encrypted store or create a new empty one that you can put files into.

Turn a folder into a secure vault

Choose the option to create a Disk Image From Folder. Select the folder in the file browser and click the Image button. You have the opportunity to give it a new name or keep the old one, and it can be compressed, which is useful if you want to save some disk space.

The most important setting though, is the encryption option. You can choose 128-bit or 256-bit AES encryption. It's very difficult to break 128-bit encryption and this is fine for preventing access by most hackers and thieves. You can use 256-bit AES to make it impossible to break into for anyone that doesn't have access to a supercomputer and lots of time on their hands. It's slightly slower, but if you've got government secrets that you need to hide then go ahead and select it.

You'll find that compressed is the default option for the Image Format setting, but if you click it, you'll see some other useful options. If you want to be able to add more files to this encrypted disk vault you must choose the read/write option instead of compressed or read-only.

Disk Utility

Go ahead and create the disk image. You'll be prompted to enter a password for it and there's a very useful password strength indicator. Long passwords that contain both numbers and upper and lowercase letters make good passwords that are hard to crack (but also hard to remember!). There is an option to remember the password in your keychain and this is ticked by default. What this means is that you don't need to enter the password every time you want to open the encrypted vault, but that defeats the purpose of creating it - if someone can log on with your account they then have access to the vault. Clear that tick and don't store the password in your keychain!

Disk Utility

Click OK and the disk image is created. The original folder is retained, so you must now delete it, leaving just the encrypted disk image - your secure vault. Drag the original folder to the Trash then hold down the Command key and right click the Trash. This enables you to securely delete the contents of the Trash folder. After all, you don't want someone to be able to recover the original folder from the Trash.

Using the disk image is easy. Double click it and you'll be prompted to enter the password (as before, don't store it in the keychain). It's then mounted like a disk drive and you can access the files and folders it contains just like any other disk. You can add more files to it if you set the read/write option when creating it.

Create a new empty secure vault

Instead of turning an existing folder into a secure vault, you can create a new empty one that you can add files and folders to later. In Disk Utility select File, New, Blank Disk Image. There are lots of advanced options here, such as the format and partitions, but you can leave them set to the defaults (it varies depending on the size, so leave them to Disk Utility to choose). The two settings you need to change are the encryption, which offers exactly the same options as before, and the size. There are several predefined sizes to choose from or you can enter your own custom size. Don't make it too small or you'll run out of space and you won't be able to make the encrypted vault any bigger.

Disk Utility

As before, you just double click the disk image file to mount it as a disk. You'll be prompted for the password and then you can use it to copy files to, move files, or save files from within applications. It's just like a regular disk drive except that when you eject it, it's encrypted and no-one can access it.