Obfuscate CakePHP Helper

By David Golding

Sometimes you may need to obfuscate your HTML markup. I know for one of my projects, I needed to set up a PayPal redirect page and didn’t want the data to be manipulated by any users, so I opted to obfuscate the markup using JavaScript functions. Obfuscation is by no means a perfect method for encrypting HTML markup, but it certainly makes hacking your stuff a pain, and generally gets the job done.

A CakePHP Helper

To simplify obfuscation methods for Cake, I put together the Obfuscate helper, which you can see below. Using it is easy. Copy the contents of the helper into the app/views/helpers/obfuscate.php file, then include the helper in your controller, like so:

var $helpers = array('Obfuscate');

Then in the view, whatever you want to obfuscate, simply run:

$obfuscate->string('Markup to obfuscate');

The Helper’s Code

Here’s the code you’ll need to copy to app/views/helpers/obfuscate.php:

<?php
/* Based on Ian Willis' iScramble PHP script: z-host.com/php/iscramble */

class ObfuscateHelper extends Helper {

/**
 * Obfuscate::_rot13()
 * ++ performs ROT13 enconding on a given string
 * @param string $str	The string to encode
 * @access private
 */
	function _rot13($str) {
	    $from = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
	    $to = 'nopqrstuvwxyzabcdefghijklmNOPQRSTUVWXYZABCDEFGHIJKLM';
	    return strtr($str, $from, $to);
	}

	/* Perform the equivalent of the JavaScript escape function */
/**
 * Obfuscate::_escape()
 * ++ Equivalent of the JavaScript escape function
 * @param string $plain	The string to escape
 * @access private
 */
	function _escape($plain) {
	    $escaped = "";
	    $passChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789*@-_+./";

	    for ($i = 0; $i < strlen($plain); $i++) {
	        $char = $plain{$i};
	        if (strpos($passChars, $char) === false) {
	        	$escaped .= sprintf("%%%02X", ord($char));
	        } else {
	            $escaped .= $char;
	        }
	    }

	    return $escaped;
	}

/**
 * Obfuscate::string()
 * ++ Obfuscates a given string
 * @param string $plain	The string to obfuscate
 * @param bool $longPwn	Whether to use more JavaScript code for better obfuscation
 * @param bool $rot13	Whether to use ROT13 encoding; takes longer to decode, not recommended for long strings
 * @param string $sorry	Markup to display if the user doesn't have JavaScript enabled in the browser
 * @return	Obfuscated JavaScript code
 * @access public
 */
	function string($plain, $longPwd=false, $rot13=false, $sorry="[Please Enable JavaScript]") {

	    $escaped = $this->_escape($plain);

	    if ($rot13) {
	        $escaped = $this->_rot13($escaped);
	    }

	    $numberOfColumns = 10;
	    $numberOfRows = ceil(strlen($escaped) / $numberOfColumns);
	    $scrambled = "";
	    $escaped = str_pad($escaped, $numberOfColumns * $numberOfRows);
	    $password = "";
	    srand(time());

	    for ($j = 0; $j < ($longPwd ? $numberOfRows : 1); $j++) {
	        $availChars = substr("0123456789", 0, $numberOfColumns);
	        for ($i = 0 ; $i < $numberOfColumns; $i++) {
	            $char = $availChars{ rand(0, strlen($availChars)-1) };
	            $password .= $char;
	            $availChars = str_replace($char, "", $availChars);
	        }
	    }

	    $scramblePassword = str_repeat($password, $longPwd ? 1 : $numberOfRows);
	    $scrambled = str_repeat(" ", $numberOfColumns * $numberOfRows);
	    $k = 0;

	    for ($i = 0; $i < $numberOfRows; $i++) {
	        for($j = 0; $j < $numberOfColumns; $j++ ) {
	            $scrambled{(((int)$scramblePassword{$k}) * $numberOfRows) + $i} = $escaped{$k};
	            $k++;
	        }
	    }

	    $javascript = "<SCRIPT>\n\n</SCRIPT>\n";
	    $javascript .= "<NOSCRIPT>\n$sorry\n</NOSCRIPT>\n";

	    return $javascript;
	}
}
?>

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