[RC5] Solutions for a faster DES-II-3

Jocelyn Doire jdoire at cslo.consultronics.on.ca
Thu Jul 30 01:11:56 EDT 1998


It took 2.4 days to crack DES-II-2, now we will have only a 
quarter to that time, or about 14 hours!

We need to go much faster to have a chance to win!  And we need to 
start faster, much faster!

Here's a plan that can help to start faster:

There two main obstacles for starting faster: 1) client start
cracking only after connecting to the server and get the signal that
the contest has started. 2) it takes hours to retrieve the first
blocks to crack, because the key server is overloaded.

1) The first problem can be easily resolved by adding a timer into
the client. When a client connect to a server, on top of getting
blocks, they could get the time when the contest starts. If it is
within 24 hours, let's say, the client would start a timer, and when
the time come, would stop cracking RC5, and start to retrieve blocks
for the DES contest.

2) The second problem is caused by the heavy traffic when the contest
start, and to speed up the start, the traffic have to be reduced to
the minimum. This can be achieved by separating the encrypted message
from the blocks, and by sending the blocks well in advance and by
sending the encrypted message only once, when the contest starts.

The first part is relatively easy to do, I think, but second part 
will require a lot more work, given that almost every element of 
d.net needs to be changed, including  the buffer structure, client, 
proxy, server.

A time script could look like that: At T-24h(variable), the client
connect and is told that the contest starts in 24 hours. At T-12h,
the client retrieves DES blocks in advance. T-1min, the clients stop
cracking RC5, and start to ask for the DES encrypted message.

Given the complexity of the process, I think we should do two or 
three rehearsals before the contest. I suggest that we try to crack 
DES-II-2, and see if we can make it under 14 hours.

Someone in the #distributed (that will remain anonymous...so that he
does not have to hide from everyone... :-) told me that we had six
months before the next contest, so had plenty of time! Well, I beg
to differ, lots of client were updated very late, and for myself, I
finally got the MMX version two days AFTER the contest was started!
No, we don't have much time!

I know that most, if not all, of the programmers are busy guys, but
if we care of having a chance to win the next contest, the
programmers must get cracking now!

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