Just how secure is an encrypted disk image?

motulist

macrumors 601

Original poster

• Mar 26, 2007

• #1

How secure is an encrypted disk image? Assuming the password isn't discovered by other means, is a 128 encrypted disk image breachable by any sub-FBI supercomputer means? Could any information be pulled out, such as file names, even if they aren't loadable?

 

Eidorian

macrumors Penryn

• Mar 26, 2007

• #2

Here's a start. Remember to use secure virtual memory!

 

motulist

macrumors 601

Original poster

• Mar 26, 2007

• #3

Eidorian said:

Here's a start. Remember to use secure virtual memory!

Click to expand...

DOH! 10.3.9 doesn't have a checkbox for secure virtual memory in the security pref pane. At least not when file vault is turned off. I didn't think file vault had to be turned on for my encrypted disk images to be totally secure.

 

mkrishnan

Moderator emeritus

• Mar 26, 2007

• #4

Eidorian said:

Here's a start. Remember to use secure virtual memory!

Click to expand...

I'm not super technical...but a lot of these issues are unique to FileVault and not a general characteristic of OS X's implementation of AES-128 encrypted disk images, correct?

Although the secure VM is a good issue, since the VM file potentially has sensitive data in it.

 

Eidorian

macrumors Penryn

• Mar 26, 2007

• #5

mkrishnan said:

I'm not super technical...but a lot of these issues are unique to FileVault and not a general characteristic of OS X's implementation of AES-128 encrypted disk images, correct?

Although the secure VM is a good issue, since the VM file potentially has sensitive data in it.

Click to expand...

The strength should be based on AES-128 and the user's password.

 

mkrishnan

Moderator emeritus

• Mar 26, 2007

• #6

Eidorian said:

The strength should be based on AES-128 and the user's password.

Click to expand...

Also make sure you are not set up to automatically log into the disk image using your login keychain, natch, as that pretty much defeats the security entirely. 😀

 

Eidorian

macrumors Penryn

• Mar 26, 2007

• #7

mkrishnan said:

Also make sure you are not set up to automatically log into the disk image using your login keychain, natch, as that pretty much defeats the security entirely. 😀

Click to expand...

A login window is a must.

 

motulist

macrumors 601

Original poster

• Mar 26, 2007

• #8

mkrishnan said:

Also make sure you are not set up to automatically log into the disk image using your login keychain, natch, as that pretty much defeats the security entirely. 😀

Click to expand...

Yeah, I think it's terrible security that the remember password checkbox is checked by default.