lxg » password

November 19th, 2008 at 12:29 pm

Lightweight password generator

Here’s a snippet of PHP code that can create passwords. It can create passwords of different lengths, it can use different sets (uppercase and lowercase letters as well as numbers), and it can be told to exclude potentially confusing characters.

<?php
function passgen($length=8, $reqsets='uln', $noconfusing='true')
{
	$length = (int)$length;
	if ($length > 20 || $length < 3) $length = 8;
 
	// some characters look alike. let's optionally exclude them.
	$confusing = ($noconfusing === 'true') ? 'O01Il' : '';
 
	$randchars = $token = '';
 
	$sets = array(
		'u' => 'ABCDEFGHIJKLMNOPQRSTUVWXYZ',
		'l' => 'abcdefghijklmnopqrstuvwxyz',
		'n' => '0123456789'
		// you can even add an own set
	);
 
	if ($reqsets)
	{
		$reqsets = str_split($reqsets);
		foreach ( array_keys($sets) as $availset )
			if ( in_array($availset, $reqsets) )
				$randchars .= $sets[$availset];
	}
 
	if (!$randchars)
		$randchars = implode($sets);
 
	for ($i=0; $i<=$length; $i++)
	{
		do
		{
			$lpos = mt_rand( 0, strlen($randchars)-1 );
			$letter = substr($randchars, $lpos, 1);
		}
		while ( in_array($letter, str_split($confusing) ) );
 
		$token .= $letter;
	}
	return $token;
}
 
echo passgen($_GET['length'], $_GET['sets'], $_GET['noconfusing']);
?>