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Cryptography and CS and Politics (sort-of) - Jim Huggins
January 2nd, 2008
05:24 pm
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Cryptography and CS and Politics (sort-of)
Ok ... if you're not a CS geek, you may want to skip this ...

Some smart CS folks, claiming omniscence, have predicted exactly who will win the 2008 U.S. Presidential Election.  Except that, of course, they don't want to tip their hands to the betting public.  So, instead, they created a document containing their prediction, saved it, computed an MD5 hash of the prediction file, and published the MD5 hash on their webpage.  Once the election happens, they'll publish their prediction file, and anyone can run MD5 on the file to verify that they had made the prediction a full year before the election.

Except, of course, they haven't.  What they have done is taken a previously-published vulnerability with the MD5 algorithm and executed a dramatic proof-of-concept.  They've created twelve different prediction files, very carefully, in such a way so that all twelve files have exactly the same MD5 hash.  Thus, it doesn't matter who wins; they'll take whoever wins and publish his/her prediction file.

In cryptography, we call this situation a collision: a case where two (or more) inputs to a hash function produce the same output.  Cryptographic hash functions are frequently used like signatures to verify the integrity of a message. It is thus important that such functions be collision-resistant: that is, it should be extremely difficult to find (or construct) a collision for a given hash function.

I could spend a lot of time writing formulas on a whiteboard illustrating the concept.  But these folks have done it far more dramatically.  Cool.

Current Mood: chipperprofessorial
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From:wildirishrose80
Date:January 3rd, 2008 12:12 am (UTC)
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That could make this year's Cryptography classes fun. :)
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From:darthdingus
Date:January 3rd, 2008 05:50 am (UTC)
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Who is teaching Crypto next summer anyway? I'mma take it as one of my last four classes...
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From:jkhuggins
Date:January 3rd, 2008 12:03 pm (UTC)
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(a) I'm not sure we're offering Crypto next summer, but it's certainly possible. (b) The class tends to rotate between myself, Geske, and Cater, depending on what other classes need to be offered.
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From:darthdingus
Date:January 3rd, 2008 06:19 pm (UTC)
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I talked with Dr. Geske at the end of the term and he thought it should be offered next summer, as it wasn't offered as a full class last summer. I know Mr. Elder had you for an independent study in it last summer, though. If it doesn't get offered, I'd like to do something similar.
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From:jkhuggins
Date:January 5th, 2008 02:05 pm (UTC)
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If Geske said it's likely to be offered, then there's a good chance of it. Geske is the one who puts the schedule together ...
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From:kevinmt
Date:January 4th, 2008 12:05 am (UTC)

CS Department Changes

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The CS department is undergoing some exciting changes, unfortunatly I'm a little late to take full advantage. Hopefully with accreditation and the new concentrations we can get enrollment up and beable to offer the new classes a little more often.
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From:jkhuggins
Date:January 5th, 2008 02:05 pm (UTC)

Re: CS Department Changes

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Thanks for the encouraging word. (Yeah, new stuff always comes a little too late for current students.)
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