Secure IDE?

Peter Gutmann pgut001 at
Thu Jul 31 08:23:39 PDT 2003

"Trei, Peter" <ptrei at> writes:

>It's a move in the right direction, but I wish they had followed through and
>done the right things:
>* [AES | 3DES]/CBC 

I get the feeling they use ECB for speed (heavy pipelining) rather than

>with a good distribution of IVs

Where would you store them?  The feature of this is that it's fully
transparent, so you can't store IVs anywhere.

>* User-generated keys (before initial disk setup, of course).

That one's the only thing I can't find a good technical reason for... perhaps
it's just commercial, since they see the dongles as a revenue source and will
sell you software to set up n dongles yourself, where price is proportional to

>* Some kind of PIN or password protection on the dongle.

How would you do this without a custom BIOS (remember that their general
product is for dropping into any PC)?

>40 bit DES is not secure against your kid sister (if she's a cypherpunk :-),
>much less industrial espionage.

I'm more worried about key backup - it's bad enough having cheapest-possible-
components IDE drives without complicating it further with a second point of
failure.  In the meantime a better option is still the triumvirate of:

- Sensitive data saved only to RAM disk.

- 3DES-encrypted volume mounted as a filesystem, which I can back up in
  encrypted form if necessary, and with all crypto done in software with per-
  sector random IVs, user-generated keys, and all the other stuff you asked

- Encrypted swap.

(Oh yeah, and a UPS so you're not tempted to temporarily save stuff to disk
 elsewhere in case the RAM drive goes away suddenly).

>"40-bit DES (US Data Encryption Standard) is adequate for general users"
>Yeah. Right.

If you're worried about Joe Burglar grabbing your laptop (for the value of the
laptop) and your business data being leaked as collateral damage, or someone
stumbling across your warez or pr0n, then it's probably adequate.  Since this
is what general users would be worried about, I'd agree with the statement.
Anyone worried about more than that (probably about 0.01% of the market) isn't
a general user any more.


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