Example of Pack()

[ziggs]

Hello, if you know what this Subject line means I am impressed. If not then go to www.php.net and type in Pack in the Search functions list...read...and come back. Ok now that we are all refreshed with this. . HOW DO I USE IT!?! Lets say that I have a password of ABC123. I need to break it down to Binary form. How the heck can I use Pack to do it? It says it will take a string and break it to binary. Well how can I do that? Then use the unpack to get it back to its original form? PHP.net really didn't explain it very clearly in my mind. Hope someone can help. Thanks!
Ziggs

[van__]

Here's a real rudimentary bit of code to pack text into a binary string with pack and unpack back into human readable chars:

<?
$str = "TEXT_MESSAGE";

//the easy part is 'encrypting' it...
for($i=0;$i<strlen($str);$i++) { $enc .= pack('C',decbin(ord(substr($str,$i,1)))); }
echo "Here's the binary output<br>\n";
echo $enc;

//now to decode...
$dump = unpack('C*',$enc);
echo "<p>Here is what we found...</p>\n";
print_r($dump);

foreach ($dump as $key=>$val) {
for ($x=0;$x<(8-strlen($val));$x++) { $val .= '0'; }
$test = chr(decbin($val));
	if (ord($test) < 255) {
  $str .= $test;
  }
}

echo "<p>And here's the decrypted string: " . $str;

?>

...now, you can learn all about bitmasking by reading up on bitwise operators to shuffle the binary data to actually create a cypher.

Enjoy