Andrew Hill ahill at vision.net.au
Thu May 28 17:39:16 EDT 1998

Hash: SHA1

At 10:36 27/05/98 -0700, you wrote:
>Quick question, what is RC5-64 bit in terms of RC5-??/??/?? I mean
>size, rounds etc...?
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majordomo at lists.distributed.net

Thanks for the mail, the RC5 is a encryption algorithm being sold and
devoloped by RSA. http://www.rsa.com/rsalabs/  RC5-64 is a encryption
method using a 64 bit key. There is much more info at
http://www.distributed.net/rc5/ on the algorithm, but the word size
and rounds and key lenght are variable. One example was RC5,32,16,7
which would be 32 bit word inputs and outputs, 16 rounds and a 7 byte
(56 bit) key.

RSA in particular have a contest for groups of people to try and crack
their algorythms. Recently, the 56 bit key fell. The main attack is to
use the distributed computing resources that are available on the
internet. If you look at http://www.distributed.net/rc5/ you will see
the site that I support. Myself I am part of the group Australian
Dudes. Were doing OK. The main thing is you begin to realise how much
computing power is out there (sounds like the x files).

However, the 64 bit key looks as if it is going to take a long will to
brute force crack it. So on PGP5 I use 2048 bit key and to me that
means that unless someone knows of a weakness in the program or
someone has a new method of factoring prime numbers you email is safe
from prying eyes if you use PGP. That is unless someone can access
your computer and knows your pass phrase.

If you have the time take a look at these sites they are interesting
and sooner or later we all must get into net security and privacy.

Version: PGPfreeware 5.5.3i for non-commercial use <http://www.pgpi.com>


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