Impelled by boredom and procrastination, I’ve packaged up a propositional logic minimizer I wrote last Summer. It’s a cute little thing, written in Python. I used it for optimizing queries on a bioinformatics graph database, but it’s a generally handy thing.
Filed by Michael Greenberg on 2006-07-13 at 7:59am under Software
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The NeoSmart files has a brief commentary on the feasability of encoding schemes like PHPEnkoder.
On one side, his argument is pretty strong. Any spammer could use Greasemonkey to drive harvesting — complete DOM, complete JavaScript. But there are two points I disagree with him about.
First, he mentions that
JavaScript was never meant to be used as a heavy cavalry, a knight in shining armor, or else a bit of code that can may be used to do anything - because it’s not.
On the one hand, this has historical precedence. For example, much of the damage done by COBOL was due to its abuse. It was a small scripting language that exploded. But it’s also a bit senslesss. COBOL was crippled on day one. Syntactically and semantically, I mean. JavaScript, with its anonymous functions and prototype object system, remains state-of-the-art today. Just because JavaScript was a glue-script language when it was born doesn’t mean it can’t be useful now as a general-purpose language. Or should ML only be used to write theorem provers? Should Smalltalk only be used to teach children? JavaScript is not Tcl, and it’s not Perl. JavaScript has some great features, a light syntax, and a huge user base. While it’s true that browser incompatabilities are a problem, toolkits seem to have dealt with this well.
But I’m not going to argue languages with someone who prefers VBScript to JavaScript. The important thing is that I think he missed an important capability of the Hivelogic algorithm, something that makes it much more powerful than it seems.
PHPEnkoder is just a port of a very creative piece of software, the Hivelogic Enkoder. The original Enkoder takes a string and encodes it by, say, swapping every other letter. It then tacks on some JavaScript to swap them back. This is already a pretty strong system. But then it goes on and encodes that JavaScript, building up a tower of encoded scripts. An evaluation loop calls eval, iteratively decoding until the bottom document.write is reached and the text is displayed.
What’s so special about that? Well, we can build a tower as high as we like. We can make it arbitrarily computationally intensive to decode the e-mail. Half a second? Easy, give it forty or fifty encodings. Five seconds? Sure. These “computational micropayments” can be worthwhile for a user to pay, but a spammer? Decode one, sure. Decode fifty? That’s nearly five minutes to get fifty e-mail addresses. How many of those people really need a bigger penis?
I don’t much like that future, though. Even if it’s a link a user can click to wait a minute for the e-mail address, that’s not ideal. NeoSmart is right, much of the problem can and should be solved server side. The only client side solution that will ever work will require human language: posting e-mail addresses as puns, jokes, tricks, songs. The only way to escape our symbol-processing machines is to abuse symbols: I’m Mike, and I hang out with hatted weasels! My plugin, PHPEnkoder, also spends a lot of time at the weasels’ place.
But I haven’t seemed to need either of those solutions, as I still haven’t received any spam at the addresses I’ve posted here — encoded, of course.
Filed by Michael Greenberg on 2006-07-04 at 12:27pm under Programming Languages, Software
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My other class this term is Shmuel Katz’s Formal Specifications of Complex Systems (link in Hebrew). Shmuel was my advisor here at the Technion, but I would have still taken the course if he wasn’t.
The course was very interesting, and I’ve come to a conclusion about the expressivity and usefulness of specification languages.
Filed by Michael Greenberg on 2006-07-02 at 5:35pm under Programming Languages
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