pgut001@cs.auckland.ac.nz[SMTP:pgut001@cs.auckland.ac.nz]
"Trei, Peter" <ptrei@rsasecurity.com> 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 cluelessness.
Possibly - they're using an ASIC, so I'd have thought that speed would not be the issue. I have not run the numbers.
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.
I'm not really up on crypto file systems, but I beleive at least some use the sector address as the IV. IVs don't need to be random, secret, or unpredictable - they just need to be unrepeated. (I'm assuming sector-at-a-time encryption).
* 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 n.
Having the user generate the key and load it on the dongle means that he has good assurance that the manufacturer doesn't have the key. Any kind of backup will open a possible route of attack. If the user can specify the raw key value (it's short - this is symmetric crypto), they can choose their own backup - up to and including writing it on paper and carefuly hiding it.
* 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)?
We're talking about two different products. The ABIT is a MB, presumably with it's own custom BIOS, so that's not an issue there.
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 for.
- 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.
Peter.(G)
Peter (T)
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Trei, Peter