Article View: comp.virus
Article #4701Re: How to measure polymorphism
From: David M. Chess
Date: Mon, 18 Jan 1993 21:03
Date: Mon, 18 Jan 1993 21:03
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>From: Declan Malone <maloned@ul.ie> > Now how do you measure randomness in an >objective way? You can't really, and the irony of it is that the more >you try, and the more objective/detailed your description becomes... Grep Chaitin has done some excellent work on this (he had a general- audience paper in a reasonably recent Scientific American, I think), and has perfectly objective measures of randomness that also seem to jibe very nicely with intuition. The basic idea is that you can measure the randomness of a string of bits by finding the smallest program for some standard Turing Machine that produces those bits. For a very random bitstring, of course, the smallest program simply contains the string itself as data, and prints it out. For very non-random strings (0000000...), the corresponding program is obviously simpler. (This is a very rough description; if it seems wrong to you, it probably is, and you're best off finding the original papers rather than arguing with me about it!) This agrees rather nicely with Bill Arnold's suggestion that we measure polymorphism by how many lines of code we have to add to make a detector... *8) DC
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Path: arc1-ca.pugleaf.net!sparky!uunet!ukma!cs.widener.edu!dsinc!netnews.upenn.edu!netnews.cc.lehigh.edu!news From: chess@watson.ibm.com (David M. Chess) Newsgroups: comp.virus Subject: Re: How to measure polymorphism Message-ID: <0002.9301281842.AA17847@barnabas.cert.org> Date: 18 Jan 93 21:03:05 GMT Sender: virus-l@lehigh.edu Lines: 24 Approved: news@netnews.cc.lehigh.edu