[Cryptography] [cryptography] NIST Workshop on Elliptic Curve Cryptography Standards

[Ray Dillinger]

On 05/12/2015 05:00 PM, dj at deadhat.com wrote:

> Alas, the world isn't just the internet and smart cards. We are throwing
> crypto on silicon as fast as we can to address the many threats to
> computer hardware. No one block size is correct.

Well, maybe...

How about "The block size is exactly the same as the message
size no matter what the message size happens to be?"

I know, it's a laughable idea when talking about "lightweight"
cryptography.  I can't think of any way to actually do it that
wouldn't take at least LogN times longer than a standard block
cipher with fixed-length blocks. And the idea of encrypting a
"stream" is right out unless you have a higher level of the
protocol breaking the stream up into packets of known size,
in which case you have a standard block cipher again.

But in a brute kind of way, it's very interesting for just
plain freezing out most  of the attack methodologies I'm aware
of.

No block boundaries inside the message, and every bit of the
ciphertext depending on every bit of the plaintext, means
entire classes of attacks just don't have anything to work
with.

It's a random idea.  It may have occurred to me due to lack
of sleep, or because I'd been looking at C++ template code
for a block cipher that takes block size as a parameter.

				Bear			

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: OpenPGP digital signature
URL: <http://www.metzdowd.com/pipermail/cryptography/attachments/20150513/68218686/attachment.sig>