[RC5] Re: CSC vs rc5

abigail at delanet.com abigail at delanet.com
Thu Dec 30 04:44:50 EST 1999


> Date: Tue, 21 Dec 1999 10:11:10 -0800
> From: Jason Hartzell <jason_hartzell at lvcm.com>
> Subject: [RC5] CSC vs rc5
> 
> >Why? People aren't in for the money, the expected income is just not enough. 
> >
> >I don't mind wasting my spare CPU cycles to something I can see some interest
> 
> This is just another case of a fundamental lack of understanding
> regarding cryptography. The misconception that all 56-bit encryption is
> the same. If that's the case, then why is CSC taking so much longer than
> the last DES. Why did RC5-56 take longer than CSC and DESIII combined.

56 bits is 56 bits. Assuming no additional requirements on keys that
effectively reduce the key space, CSC with 56 bit keys, DES with 56
keys and RC5 with 56 keys all had 72057594037927936 keys to be checked.
The only difference is the time it takes to encoded a message. Algorithmic
effects, with a small role for the size of the key, but otherwise
independent of the key space. It's already been proven that going through
a 56 bit keyspace can be done fast. It it takes 4 times as long to do
one encoding, you need 4 times as much time.

> Cracking CSC does prove something, and provides the "break" that 90% of
> all participants were screaming for about six months ago. You remember,

No, I don't.

> when everyone wanted more short term projects so that they could get a
> feeling of accomplishment.

"Everyone" would include me, and I certainly have never screamed for a
short term project. 

>                            Now that the short term project is here they
> don't want to bother so that they can pad stats in RC5-64. Pretty
> stupid.

That's an opinion, not a fact.

>         Some people just don't get that there is only one block in the
> entire RC5-64 project that is worth caring about.

As opposed to the 10,000 blocks worth caring about in CSC, and the
half a million blocks in DES-III?

>                                                   Oh well, and you
> wonder why the corporation wants to lock IT in the closet because they
> are just too stupid to get it..

No, I don't wonder about that. What I do wonder is about the relevance of
your last sentence to the rest of your argument. I don't seem to get it.


I don't care if people crack CSC blocks. But what itches me is that for
many moons, people were happely cracking RC5-64 blocks, then we have
some CSC clients, and suddenly we're all being pushed into CSC as if
it's the best thing since sliced bread. It has be almost made remove
the distributed net client of my computer and have me switched to some
other project. Do we really have a "CSC stats now available" on every
single RC5 page? Blech. It gives the taste of a bad marketing campaign.


Abigail

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