[liberationtech] secure wipe of flash memory

[Michael Rogers]

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Hi James,

To follow up on this, TrueCrypt uses XTS mode, which as far as I can
tell is designed to protect against an adversary who can read multiple
versions of the ciphertext:

https://en.wikipedia.org/wiki/Disk_encryption_theory#Problem_definition

However, if a flash storage device contains a journalling filesystem
or the controller chip uses journalling, the adversary may be able to
tell when each block of the encrypted volume was updated, which might
reveal the presence of a hidden volume:

http://www.truecrypt.org/docs/?s=journaling-file-systems

Does anyone on the list know whether flash controller chips use
journalling? I'm guessing they might because YAFFS does.

Cheers,
Michael

On 17/07/12 00:48, James Vasile wrote:
> Thanks, Michael.  That's a good thought.  I hadn't factored in the 
> notion of having multiple versions of the ciphertext.  I'll take a
> look at some disk-encryption systems with that in mind.
> 
> -J

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