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Totally Unintelligible Code (Takes Brains To Write)

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Totally Unintelligible Code (Takes Brains To Write)

· Web Dev Zone ·
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Learn how error monitoring with Sentry closes the gap between the product team and your customers. With Sentry, you can focus on what you do best: building and scaling software that makes your users’ lives better.

By totally unintelligible, I mean this:

_=[]|[];$=_++;__=(_<<_);___=(_<<_)+_;____=__+__;_____=__+___;$$=({}+"")[_____]+
({}+"")[_]+({}[$]+"")[_]+(($!=$)+"")[___]+(($==$)+"")[$]+(($==$)+"")[_]+(($==$)
+"")[__]+({}+"")[_____]+(($==$)+"")[$]+({}+"")[_]+(($==$)+"")[_];$$$=(($!=$)+""
)[_]+(($!=$)+"")[__]+(($==$)+"")[___]+(($==$)+"")[_]+(($==$)+"")[$];$_$=({}+"")
[_____]+({}+"")[_]+({}+"")[_]+(($!=$)+"")[__]+({}+"")[__+_____]+({}+"")[_____]+
({}+"")[_]+({}[$]+"")[__]+(($==$)+"")[___]; ($)[$$][$$]($$$+"('"+$_$+"')")();

That's JavaScript, written by Yosuke Hasagawa (who is kind of insane..ly awesome). Without any alphanumeric characters. What does it do? Run it and see. (Won't mess anything up, promise.)

How does it work? Well, some quirks of JavaScript, activated by a UTF-8 geek's incredible patience. But you can do something similar in PHP, as Fredrik Nordberg Almroth did:

<?=($_=@$_GET[2]).@$_($_GET[1])?>

Okay, so there's a GET in there, which makes a little more sense. (Or not, in which case, see Fredrik's explanation.) But what about totally non-alphanumeric PHP?

Try this:

<?
$_="";
$_[+""]='';
$_="$_"."";
$_=($_[+""]|"").($_[+""]|"").($_[+""]^"");
?>
<?=${'_'.$_}['_'](${'_'.$_}['__']);?>

From this slick blogpost.

At this point you might (rightly) wonder why I'm posting more non-alphanumeric characters. It's just the wrong encoding, you'll say. True; but re-encoding code can help you push a language's boundaries just a tad..and these are as purely code as any cryptographer's problem, and yet actually execute in a real programming language you already know.

And if you want a more complete explanation, check out the follow-up to the last post cited, with full explanatory slides.

What’s the best way to boost the efficiency of your product team and ship with confidence? Check out this ebook to learn how Sentry's real-time error monitoring helps developers stay in their workflow to fix bugs before the user even knows there’s a problem.

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