All

nice obsfu generator at..

http://sandgnat.com/cmos/cmos.jsp

--
Martin Hepworth
Snr Systems Administrator
Solid State Logic
Tel: +44 (0)1865 842300


Scott A Crosby wrote:
On Mon, 28 Feb 2005 15:34:13 +0000, [EMAIL PROTECTED] (Justin Mason) writes:


A paper at the spam conference suggested using an Edit Distance algorithm
with very good results; the idea being, the edit distance from "cialis" to
"C 1 a l | s" isn't as far as it is to "specialized" or so on.

if I recall correctly, someone submitted an implementation quite a while
ago on our BZ, but I think the FP rates were too high.   Given the
recent paper's published results, though, it may be there are good ways
to tweak it to get FPs at a tolerable rate.


I did an implementation of it some time ago, but I didn't get a chance
to take it far enough to test out its effectiveness. I heard remarks
that naively applying edit distance is too slow. To avoid having a FP
rate that was too high, the edit-distance costs are paramaterized, so
some edits are much cheaper than others. Eg.

# Cost of replacing a character with a punctuation in the obfu.
setreps ("bcdfghijklmnpqrstvwxyz","*?.-",.08);
setreps ("aeiou","*?.-",.03);

# Cost to insert these into the obfuscated string is cheap
setins ("/\|()=-'!*`;:?+[]\"^",.01);
setins ("_,.",.01);

So, 'v.agr.' and 'v..ia...gra' both cost <.10


Got a bugzilla# that I can attach the prototype code to? (Also, is it possible to report a bug/attach the code without creating a bugzilla account?)

Scott

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