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Subject: q&d comparison (was Re: [Cryptix-Users] Rijndael - the real work now begins)
From: Ian Grigg (iangsystemics.com)
Date: Sun Oct 08 2000 - 11:32:19 CDT

Fred Baube wrote:

> Would someone like to make a quick 'n dirty comparison among
> DES, 3DES, and Rijndael in terms of key entropy required and
> processing time required ? Give us all some quantifiable
> motivation to switch ASAP ...

There is plenty of stuff on the NIST site, but you'd have to dig
for it. There are lots of comparisons in the NSA report.

Some early results say that Rijndael is about 40% (256) and 90%
(128) faster than DES in encryption (decryption is slightly
slower than those speedups).

Key set up is about 5 times faster than DES (encryption) and
3 times faster than DES (decryption) with some drop off (4, 2.5)
for 256 bit keys.

On the amount of entropy, well, I'd leave that to a cryptographer,
other than the observation that Rijndael has 128, 192, 256 bit keys,
whilst DES has 56 bits and T-DES has 168 (full).

That's very quick and dirty, and all I'm doing is calculating from
various tables floating around, and not all results are on highly
optimised versions. Hardly scientific. Also, you didn't mention
platform, which could be Java, C, Hardware, or any other...

The best bet is to run your own tests on your own platform and
see what you get.

iang