gencoder help

[pneudralics]

Can someone please explain how to work gencoder? All it is is a file. I'm still new to php and came along this. How to I encrypt files with this? Does this file need to be install somewhere on the server for the encrypted files to work? All I got from the download was a php file with the following:

<?
/*============================================================
gencoder v1.0 copyright (c) 2001
==============================================================
gencoder is a simple php encoder that use base64 algorithm to 
encode and decode the script. the drawback of this script:
- it doesn't have a key for encryption / decryption method.
- run slower then normal php script (because it need 
  to re-read the script and decode it).
- only work on single complete php tag (one open php tag and
  one close php tag) because of limitation of eval function.
unlike zend encoder, this script won't solve your problem
from hiding the source code from advance programmer but
at least you're one step closer to making your code tougher
for people to steal.
==============================================================
this is free software. you can redistribute it and/or
modify it under the terms of the gnu general public license
as published by the free software foundation.
==============================================================
author: R. Galuh Prasetyo <[e-mail]>
============================================================*/

//detects if launch from shell or browser
if ($PHP_SELF != "") {
	//from browser
	if (!isset ($source)) {
		echo "Syntax: gencode.php?source=&lt;php_sorce_script&gt;[&dest=&lt;php_dest_script&gt;]";
		exit;
	}
	if (!isset ($dest)) $dest = $source;
} else {
	//from shell
	if (!isset ($HTTP_SERVER_VARS[argv][1])) {
		echo "\nSyntax: gencode.php <php_source_script> [php_dest_script]\n";
		exit;
	}
	$source = $HTTP_SERVER_VARS[argv][1];
	if (isset ($HTTP_SERVER_VARS[argv][2])) $dest = $HTTP_SERVER_VARS[argv][2];
}

//retrieve source code
$fs = fopen ($source, "r");
$code = fread ($fs, filesize ($source));
fclose ($fs);

//check if source already encoded
if (ereg ("^<\?/\*gencoder", $code)) {
	echo "\nWarnning, \"$source\" already encrypted by gencode!!\n";
	exit;
}

//remove php tag
$code = eregi_replace("<\?|<\?php|\?>", "", $code);

//encode by base64
$code = chunk_split (base64_encode ($code));

//generate encoded string
$decript_code = 'if($PHP_SELF!="")$s=file($PATH_TRANSLATED);else$s=file($HTTP_SERVER_VARS[argv][0]);foreach($s as $l){if(ereg("^\*/",$l))$b=false;if($b)$ss.=$l;if(ereg("^<\?/\*gencoder",$l))$b=true;}eval(base64_decode($ss));?>';
$encoded = "<?/*gencoder\n$code*/$decript_code";

//write encoded string to destination file
$fd = fopen ($dest, "w");
fwrite ($fd, $encoded);
fclose ($fd);
?>

When I ran the file in the browser I get the following:
Syntax: gencode.php?source=<php_sorce_script>[&dest=<php_dest_script>]

[bradgrafelman]

Well, here's an easy answer:

Whoever wrote this script wasn't a very good PHP programmer; they relied on register_globals being set to On and the short-tag open style (<? vs. <?PHP) to be allowed.

If you want an easy fix, try placing this at the top of the script:

extract($_GET);

[pneudralics]

Nothing changed. What is this script suppose to do when I run it?? Downloaded it from:
http://gencoder.sourceforge.net/