From: James Gray <james@...>
Date: 2008-05-23T05:05:19+09:00
Subject: Re: [SUMMARY] Obfuscated Email (#163)

On May 22, 2008, at 2:24 PM, Matthew Moss wrote:

> Welcome, Ruby coders and coderettes... Tonight we bring you the Obfu  
> Awards,
> awards given by committee (i.e. me) to those most deserving for  
> their...
> "creative" work.
>
> We're going to skip the red carpet frivolities, as we have no red  
> carpet,
> and jump right to the awards. Here they are, in no particular order  
> (except
> that of their entry).

Your summaries are always more fun than mine were!  ;)

> #### Most Painful Obfuscation
>
> The first entry from _Mikael Hoilund_ is such a dangerous minefield of
> string manipulations and punctuation, the committee could not  
> completely
> discern its operation. In particular, putting aside the call to  
> `downcase!`
> (which we managed to discern after much coffee and doses of  
> Ritalin), this
> segment of code was never fully understood:
>
>    *a=e=?=,!????,:??,?,,Email
>
> We'd ask Mikael to explain himself to the committee, but we fear the  
> medical
> consequences.

Ouch.  Let's break it down.

First we need to get it to run:

 >> Email = Object.new
=> #<Object:0x389190>
 >>    *a=e=?=,!????,:??,?,,Email
=> [61, 63, 44, #<Object:0x389190>]

It's just a really complex assignment, we can see.

   *a = …

Slurp an Array into the variable a.

   … e = …

And store the first value of that Array in e.

   … ?=, …

The ASCII value of the character = (61).

This next bit is very tricky.  I had to play with it in IRb a bit to  
figure out how Ruby parses it, but it plays out as:

   … !?? ? ?, : ??, …

The conditional is the opposite of the ASCII value of ? (always true,  
which not switches to false).  If it was true, it would become the  
ASCII value of , (44).  However, since it's always false it becomes  
the ASCII value of ? (63).

The last bit is much easier:

   … ?,, Email

That's just the ASCII value of , (44), followed by the contents of the  
Email constant.

James Edward Gray II