function generatePasswords( $howMany = 10, $length = 6, $allowedChars = NULL )
{
	if (NULL == $allowedChars) {
		$allowedChars = 'abcdefghijklmnopqrstuvwxyz0123456789';
	}
	$allowedChars 	    = (string)$allowedChars;
	$allowedCharsLength = strlen( $allowedChars );
	$allowedCharsUpper  = strtoupper( $allowedChars );

	$pwds   = array();
	$count = 0;
	while ($count < $howMany) {
		for ($j = $howMany - $count; $j--;) {
			$code   = '';
			for ($i = $length; $i--;) {
				$rand = mt_rand(0, $allowedCharsLength - 1);
				if ($rand % 2) {
					$code .= $allowedChars{$rand};
				} else {
					$code .= $allowedCharsUpper{$rand};
				}
			}
			$pwds[$code] = '';
		}
		$count = count( $pwds );
	}
	return array_keys( $pwds );
}

function generatePasswords( $howMany = 10, $length = 6, $allowedChars = NULL )
{
	if (NULL == $allowedChars) {
		$allowedChars = 'abcdefghijklmnopqrstuvwxyz0123456789';
	}
	$allowedChars 		= (string)$allowedChars;
	$allowedCharsLength = strlen( $allowedChars );
	$allowedCharsUpper 	= strtoupper( $allowedChars );

	$pwds   = array();
	$count = 0;
	while ($count < $howMany) {
		for ($j = $howMany - $count; $j--;) {
			$code   = '';
			for ($i = $length; $i--;) {
				$rand = mt_rand(0, $allowedCharsLength - 1);
				if ($rand % 2) {
					$code .= $allowedChars{$rand};
				} else {
					$code .= $allowedCharsUpper{$rand};
				}
			}
			$pwds[$code] = '';
		}
		$count = count( $pwds );
	}
	return $pwds;
}

unique password|code generator

php

PHP