FileVault on other than home directories on MacOS?

Ivan Krstić krstic at
Wed Sep 23 22:30:15 EDT 2009

On Sep 22, 2009, at 5:57 AM, Darren J Moffat wrote:
> There is also a sleep mode issue identified by the NSA

Unlike FileVault whose keys (have to) persist in memory for the  
duration of the login session, individual encrypted disk images are  
mounted on demand and their keys destroyed from memory on unmount.

> TrueCrypt on the other hand uses AES in XTS mode so you get  
> confidentiality and integrity.

XTS certainly doesn't provide cryptographic integrity. It provides  
different ciphertext malleability characteristics than CBC, in that  
you can only randomize an arbitrary 16-byte block of plaintext instead  
of being able to flip an arbitrary bit (and screw up the previous  
block). However, this comes with other costs inherent to seekable  
narrow-block encryption, so I think it's hard to argue XTS provides  
"more" integrity than CBC. Or were you referring to something else?

Ivan Krstić <krstic at> |

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