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Cryptoanalysis

Life is way too short to solve six equations with eight unknown variables.

This entry was posted on Monday, March 20th, 2006 at 10:24 and is filed under Daily Rant. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

8 Responses to “Cryptoanalysis”

  1. Varun Says:
    March 21st, 2006 at 04:18

    Good one.

    Is there any partic­ular reason why it is ‘eight unknown variables’ and not ‘seven unknown variables’? Moreover is there any reason why it is ‘six equations’ and not (say) ‘ten equations’?

  2. Ramnath R Iyer Says:
    March 21st, 2006 at 05:04

    Yes, as a matter of fact, there is a good reason.

    We were given an assign­ment to solve in Prof. Mathuria’s ‘Security Proto­cols’ course, and I have to submit it tomorrow. I’m stuck with a problem I can’t solve; maybe I’m not looking at it correctly, but I don’t think any student has been able to solve it. Anyway, there a bunch of six equations, with eight unknown variables that need to be deter­mined. Still no luck. Sigh.

  3. Varun Says:
    March 21st, 2006 at 05:49

    Hmmmm… do let us know if you manage to solve it success­fully. What is the problem by the way?

  4. D Says:
    March 21st, 2006 at 07:21

    Life is too short to figure out what is meant by ‘six equations with eight unknown variables’… Anything worse than a simple linear equation with 2 unknowns is enough to make me nice and grumpy :-)

  5. Ramnath R Iyer Says:
    March 22nd, 2006 at 02:59

    The problem state­ment is at this URL:

    http://junkland.n3rds.net/uploads/SP2_m.jpg

    Enjoy!

  6. Varun Says:
    March 23rd, 2006 at 06:13

    Any progress with this problem?

  7. Ramnath R Iyer Says:
    March 23rd, 2006 at 09:17

    Not really — the Prof hasn’t told us the correct answer, and I decided that my method was probably the best one. Let’s see.

    My guess is that the easiest way to solve it is to get a compre­hen­sive list of sci-fi movies in a plain-text format from the Internet, and match each name with a key of its own length. Then you decrypt the cipher that was created with the same key but the opposite sign, and see if it gives you another name from the same database. If it does, you have one random number.

    Follow this process for the longest two names and you have all the one-time pads and messages. The method assumes that your database includes all eight movies. If only two movies are included, then a dictio­nary attack might work instead. If the two names included are not the longest ones, then a little bit of extra guess­work might be required.

  8. Abhay Says:
    March 23rd, 2006 at 19:02

    cudnt agree more :)

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