Acorn RC5

  • Latest news
  • RC5-72 Contest
  • AUG team
  • Mailing list
  • StatsBot
  • Statistics



    The RC5-72 and DES contests

    What are the RC5/DES projects?

    This is a project incorporating thousands of computers around the globe, managed by Basicially, it is about legally decrypting messages. The RC5-72 contest is a long-term contest, and may take a couple of years to solve. These tasks are achieved by using your computer's idle time to check whether a particular key is the correct one. As thousands of computers are involved, huge tasks can be accomplished, as has been proven in's cracking of a 56 bit and a 64 bit RC5 key.

    Why would I want to join?

    The first reason is that you can win $1000 is you happen to find the correct key! The only slight problem is that the chances of this is around 18,446,743,900,000,000,000 to 1 per every key block tried.

    The second reason is fame. The more blocks you try, the higher up in the ranks you go. Also, if you have elected to join a team (similar to a lottery syndicate), your team's rank will get higher and higher. If one of the members of your team finds the correct key, a further $1000 is distributed between all the members.

    How do I become part of it?

    You will need to download a client for your particular platform in order to become connected to Visit and click on 'Moo: Download the client' to reach a listing of all different clients. From here you can download the client for any platform available; make sure you get the GUI version!

    Once you download the client, unarchive it and run it. This should bring up a new icon at the right side of the icon bar. You must set it up before usage, with your e-mail address and buffer sizes, logging, performance and startup options.

    Once you've set up the client, you may wish to join a team and bring its overll ranking up the charts. Ultimately, we wish for you to join the Acorn Users Group team, but you are not in any way obliged to.

    How do I set up the client?

    When you first load !RC5DES, it should bring up a configuration window. First of all, enter your e-mail address in the 'User' section. Leaving the 'Networking' and 'Connection' settings as they are should be sufficient for now.

    In the 'Buffers' section, you can choose how large you want your key blocks to be. Choosing a value of '28' will fetch the smallest blocks. This means that they will be decoded the quickest, but it only counts as one block on your statistics. On the other hand, choosing a value of '31' will fetch the largest blocks. This means they will take longer to decode (8 times longer over a 2^28 block), but it counts as 8 blocks on your statistics.

    Leaving all other options as they are is enough to get you started. Once you get used to the client, it is advisable to change some of the other options.

    Briefly, how is the client used?

    Once you have configured the client and it is running, a white window should open with the current status of the client. After the words 'x RC5 blocks are in file buff-out/rc5', it may seem as though nothing is happening. What is actually happening is your first block decrypting. After a while, you will see a '.' appear on the screen. If you leave it a while longer, '10%' will appear. Once this gets to '100%', a block is completed.

    If you wish to send this completed block to the server, press menu over the window, go over to 'Network' and click on 'Perform network flush'.
    Last Update: 29th September 2005