On 9/11/2015 12:06 pm, Terje Elde wrote:
On 09 Nov 2015, at 12:56, Aaron Zauner <[email protected]> wrote:
There's only one chinese team working on CAMELLIA attacks as far as I
can tell, vs. a lot of people that work on AES attacks. As people have
mentioned before: a attack that will break AES will likely also break
CAMELLIA.
Reverse is also mostly (but not certainly); If AES is secure, there’s a good
chance that Camellia is as well.
The one thing that worries me with the discussion of removing Camellia, is that
arguments for are almost always focused exclusively on a
cryptographic/mathematic perspective. The arguments are often true, valid and
good, but they’re also narrow in scope. I’m not worried about AES from a
crypto/math-perspective, what worries me is that those arguing for
Camellia-removal seem to ignore the practical aspect. It’s *far* more likely
that there’ll be an engineering-break, than a math-break. What happens if
someone finds a key-leakage issue with a hardware crypto-implementation,
allowing leaking keys between XEN-instances for example?
There seems to be an implied “the math is solid, therefor AES the algoritm is
secure, therefore all uses of AES is secure”. The first conclusion is solid,
but not the second.
I find the timing of this a bit puzzling to be honest. It’s only this very
year that we saw usage of RC4 to mitigate BEAST for example. That is, the
math-solid algoritms got shifted out by some, in favour of math-broken, because
they figured the tradeoff was better. (Lots could be said about if that was a
good call or not).
It tends not to be the crypto math that gets broken, but usage,
implementations, etc.
Tends? Absolutely guaranteed. I'm not sure there is a case in living
memory where a known-good algorithm fell.
Yes there are cases where known-deprecated algorithms fell - MD5 and RC4
for example, and noddy Wifi. Even tho MD5 fell, SHA1 is still standing,
and we've had 11 years to move off it since the shots were fired, and
still holding on.... :)
iang
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